LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW
The lanthanide (Ln) series has been attracted so much attention not only for its physical properties but also for its applications in organic synthesis and biomedical engineering. In the lanthanide chemistry, lanthanide contraction is a crucial concept meaning the gradual decrease in ionic radii as...
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| author | Noguchi, Daisuke |
| author_facet | Noguchi, Daisuke |
| author_institution_txt_mv | [
{
"author": "Daisuke Noguchi",
"institution": "Division of Education and Research Support, Graduate School of Engineering, Nagasaki University, 1–14 Bunkyo-machi, 8528521Nagasaki, Japan"
}
] |
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| description | The lanthanide (Ln) series has been attracted so much attention not only for its physical properties but also for its applications in organic synthesis and biomedical engineering. In the lanthanide chemistry, lanthanide contraction is a crucial concept meaning the gradual decrease in ionic radii as the atomic number of the Ln series increases. As a prominent chelator, ethylenediaminetetraacetic acid (EDTA) has been well-known to give stable complexes with various metals including Ln ions, resulted in forming (EDTA−4H)4− anion by deprotonation; over 100 kinds of Ln-EDTA complexes have hitherto been synthesized and structurally characterized using X-ray crystallography. While the lanthanide contraction phenomenon has been extensively studied in certain complexes of Ln, systematization on the Ln-EDTA remains inadequate though the chelates of EDTA are commonly used. Thus, this study presents a comprehensive analysis based on the data from the Cambridge Crystallographic Data Centre (CCDC). In mononuclear EDTA complexes X[Ln(EDTA−4H)(H2O)m]·nH2O (X+ = NH4+and its analogues) systematic lanthanide contraction depending on their coordination number are presented except for a few cases. However, in the case of non-mononuclear complexes or coordination polymers, the compositions become more complicated, and a greater variation in atomic bond length occurs, which is unusual for the lanthanide contraction studies in previous research. These varieties are considered to be influenced by different types of counter-cations, inorganic anions, solvent molecules and bridging O atoms from another EDTA anions. This suggests the flexibility and versatility of EDTA as a ligand. Such findings in the Ln-EDTA complexes could potentially provide us further development of a novel function in the future. |
| doi_str_mv | 10.33609/2708-129X.89.09.2023.14-34 |
| first_indexed | 2025-09-24T17:43:53Z |
| format | Article |
| fulltext |
14 ISSN 2708-129X. Укр. хім. журн., 2023
UDC 541.49: 546.723 – 54-386 doi: 10.33609/2708-129X.89.09.2023.14-34
LANTHANIDE CONTRACTION IN CHELATES
OF ETHYLENEDIAMINETETRAACETIC ACID BASED
ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.
Daisuke Noguchi
Division of Education and Research Support, Graduate School of Engineering, Nagasaki University,
1−14 Bunkyo-machi, 8528521 Nagasaki, Japan
e-mail: a.chemist.noguchi.d@gmail.com
The lanthanide (Ln) series has been attracted so much attention not only for its physical
properties but also for its applications in organic synthesis and biomedical engineering. In
the lanthanide chemistry, lanthanide contraction is a crucial concept meaning the gradual de-
crease in ionic radii as the atomic number of the Ln series increases. As a prominent chelator,
ethylenediaminetetraacetic acid (EDTA) has been well-known to give stable complexes with
various metals including Ln ions, resulted in forming (EDTA−4H)4− anion by deprotona-
tion; over 100 kinds of Ln-EDTA complexes have hitherto been synthesized and structural-
ly characterized using X-ray crystallography. While the lanthanide contraction phenomenon
has been extensively studied in certain complexes of Ln, systematization on the Ln-EDTA re-
mains inadequate though the chelates of EDTA are commonly used. Thus, this study presents
a comprehensive analysis based on the data from the Cambridge Crystallographic Data Centre
(CCDC). In mononuclear EDTA complexes X[Ln(EDTA−4H)(H2O)m]·nH2O (X+ = NH4
+ and
its analogues) systematic lanthanide contraction depending on their coordination number
are presented except for a few cases. However, in the case of non-mononuclear complexes or
coordination polymers, the compositions become more complicated, and a greater variation
in atomic bond length occurs, which is unusual for the lanthanide contraction studies in
previous research. These varieties are considered to be influenced by different types of coun-
ter-cations, inorganic anions, solvent molecules and bridging O atoms from another EDTA
anions. This suggests the flexibility and versatility of EDTA as a ligand. Such findings in the
Ln-EDTA complexes could potentially provide us further development of a novel function in
the future.
Keywords: coordination compound, f-block, rare-earth element, polyaminocarboxylic
acid.
15https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
INTRODUCTION. Lanthanides (Ln) have
been the extensive subject aimed at elucidat-
ing their characteristics, namely electronic,
magnetic, and optical properties, besides other
aspects such as applications in the catalysts of
organic syntheses and the agents in biomedical
engineering [1−3]. In lanthanide chemistry,
a key concept called ‘lanthanide contraction’
refers to the gradual decrease in ionic radii as
the atomic number of the lanthanide series in-
creases [4−6]. The cases of lanthanide contrac-
tion were first studied in simple binary com-
pounds [7]. Subsequently, renewed interest led
to further studies of several families of coor-
dination compounds in the solid state, and it
was found that lanthanide contraction reduces
the coordination numbers for some complexes
having rigid ligands [8−10]. Moreover, such
knowledge of the lanthanide contraction in the
well-characterized complexes has led to the de-
velopment of a novel phenomenon, for example,
‘switching photochromism’ in coordination
polymers [11]. Nevertheless, the series whose
lanthanide contraction clarified doesn’t cover
all the existing complexes with various ligands.
As one of the most prominent chelators,
ethylenediaminetetraacetic acid (EDTA; see
Figure 1) is of great interest not only in chemi-
cal analysis, but also in the advancement of ma-
terials science. One example of its potential ap-
plications involves gas storage and separation
in metal-organic frameworks (MOFs) [12].
This is due to its ability to form stable com-
plexes with practically all metal ions, including
trivalent lanthanides, where EDTA molecules
are deprotonated to form a tetravalent anion;
i.e., (EDTA−4H)4− [13−16].
So far, over one hundred EDTA complexes
of lanthanide have been synthesized and cha
racterized using X-ray crystallography [17].
Earlier studies have suggested evidence of the
lanthanide contraction in a series of Ln-EDTA
complexes with coordinated water molecu
les [18−25]. However, despite the existence
of more than one hundred various types of
Ln-EDTA complexes with reported crystal
structures [17], systematic demonstration of
the distances between centered Ln ions and
coordinated atoms, depending on the coordi-
nation numbers, is yet to be presented.
Fig. 1. A chemical structure of (EDTA−4H)4−
representing the tetravalent anion where four hyd
rogen atoms are deprotonated from EDTA mole-
cule.
As to the Ln-EDTA complexes, a systematic
comprehension of the lanthanide contraction
could be expected to provide us some addi-
tional insights into lanthanide chemistry, in-
fluenced by counter-cations, crystal solvents,
crystal packing effects, and so on. Therefore,
I report herein a comprehensive investigation
into the lanthanide contraction of the com-
plexes of Ln-EDTA based on the crystal data
that is free available from the Cambridge Crys-
tallographic Data Centre (CCDC).
EXPERIMENT AND DISCUSSION OF
THE RESULTS. A total of 111 kinds of Ln-
EDTA complexes were identified and summa-
rized along with their respective coordination
numbers (CN), excluding promethium (Pm),
which was not examined due to its radioactivi-
ty as usual, and thulium (Tm), the second-least
[8−10]. Moreover, such knowledge of the lanthanide contraction in the well-characterized complexes
has led to the development of a novel phenomenon, for example, ‘switching photochromism’ in
coordination polymers [11]. Nevertheless, the series whose lanthanide contraction clarified doesn’t
cover all the existing complexes with various ligands.
As one of the most prominent chelators, ethylenediaminetetraacetic acid (EDTA; see Figure
1) is of great interest not only in chemical analysis, but also in the advancement of materials science.
One example of its potential applications involves gas storage and separation in metal-organic
frameworks (MOFs) [12]. This is due to its ability to form stable complexes with practically all metal
ions, including trivalent lanthanides, where EDTA molecules are deprotonated to form a tetravalent
anion; i.e., (EDTA−4H)4− [13−16].
Fig. 1. A chemical structure of (EDTA−4H)4− representing the tetravalent anion where four hydrogen atoms
are deprotonated from EDTA molecule.
So far, over one hundred EDTA complexes of lanthanide have been synthesized and
characterized using X-ray crystallography [17]. Earlier studies have suggested evidence of the
lanthanide contraction in a series of Ln-EDTA complexes with coordinated water molecules [18−25].
However, despite the existence of more than one hundred various types of Ln-EDTA complexes with
reported crystal structures [17], systematic demonstration of the distances between centered Ln ions
and coordinated atoms, depending on the coordination numbers, is yet to be presented.
As to the Ln-EDTA complexes, a systematic comprehension of the lanthanide contraction
could be expected to provide us some additional insights into lanthanide chemistry, influenced by
counter-cations, crystal solvents, crystal packing effects, and so on. Therefore, I report herein a
comprehensive investigation into the lanthanide contraction of the complexes of Ln-EDTA based on
the crystal data that is free available from the Cambridge Crystallographic Data Centre (CCDC).
EXPERIMENT AND DISCUSSION OF THE RESULTS. A total of 111 kinds of Ln-EDTA
complexes were identified and summarized along with their respective coordination numbers (CN),
excluding promethium (Pm), which was not examined due to its radioactivity as usual, and thulium
(Tm), the second-least abundant of the lanthanides. Therefore, in the present article, I only deal with
each EDTA complex of Ln; La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Lu, as per my
previous work [26]. Some cif files deposited on CCDC couldn’t be opened (3D Structure
Unavailable) by the crystal viewer software Mercury.
Complexes could be classified into two categories in general terms: mononuclear complexes
and non-mononuclear ones (= metal coordination polymers). In the latter, EDTA anions act as a
bridging ligand between centered Ln cations. A typical mononuclear Ln-EDTA complex with three
16 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
abundant of the lanthanides. Therefore, in the
present article, I only deal with each EDTA
complex of Ln; La, Ce, Pr, Nd, Sm, Eu, Gd,
Tb, Dy, Ho, Er, Yb and Lu, as per my previous
work [26]. Some cif files deposited on CCDC
couldn’t be opened (3D Structure Unavailable)
by the crystal viewer software Mercury.
Complexes could be classified into two ca
tegories in general terms: mononuclear com-
plexes and non-mononuclear ones (= metal co-
ordination polymers). In the latter, EDTA an-
ions act as a bridging ligand between centered
Ln cations. A typical mononuclear Ln-EDTA
complex with three coordinated water mole-
cules [27] were shown in Figure 2. Monomeric
complexes with formulae X[Ln(EDTA−4H)
(H2O)m]·nH2O, where X+ = NH4
+, MA+
(= CH3NH3
+), N2H5
+, and Gu+ (= C(NH2)3
+),
with Ln = Ce−Nd, Sm−Er were hit by search
in the CCDC; Gu2[Ln(EDTA−4H)(H2O)2]
ClO4·6H2O (Ln = Er, Yb, and Lu) are also
included. Hereafter, some abbreviations,
‘NH4-Er’ are used for NH4[Ln(EDTA−4H)
(H2O)2]·5H2O, for example, in which EDTA
anion and water molecules are omitted. Bond
parameters for these isostructural compounds
X[Ln(EDTA−4H)(H2O)m]·nH2O are listed in
Table 1-5; d(Ln-N), d(Ln-OAc), and d(Ln-Ow)
are mean bond distances between centered Ln
atoms and corresponding coordinated atoms;
N = nitrogen atoms in the ethylenediamine
moiety of EDTA anions, OAc and Ow = oxygen
atoms in -COO− and H2O, respectively.
Fig. 2. An example of Ln-EDTA complexes with
three coordinated water molecules:
[Eu(EDTA−4H)(H2O)3]
− moiety is demonstrated
in the crystal of NH4[Eu(EDTA−4H)(H2O)3]·5H2O
[27]; where Eu (red purple), O (red), N (blue), and
C (gray). H atoms, NH4
+ (counter cation), and
crystalline water molecules uncoordinated to Eu3+
are omitted.
coordinated water molecules [27] were shown in Figure 2. Monomeric complexes with formulae
X[Ln(EDTA−4H)(H2O)m]·nH2O, where X+ = NH4
+, MA+ (= CH3NH3
+), N2H5
+, and Gu+ (=
C(NH2)3
+), with Ln = Ce−Nd, Sm−Er were hit by search in the CCDC;
Gu2[Ln(EDTA−4H)(H2O)2]ClO4·6H2O (Ln = Er, Yb, and Lu) are also included. Hereafter, some
abbreviations, ‘NH4-Er’ are used for NH4[Ln(EDTA−4H)(H2O)2]·5H2O, for example, in which
EDTA anion and water molecules are omitted. Bond parameters for these isostructural compounds
X[Ln(EDTA−4H)(H2O)m]·nH2O are listed in Table 1-5; d(Ln-N), d(Ln-OAc), and d(Ln-Ow) are mean
bond distances between centered Ln atoms and corresponding coordinated atoms; N = nitrogen atoms
in the ethylenediamine moiety of EDTA anions, OAc and Ow = oxygen atoms in -COO− and H2O,
respectively.
Fig. 2. An example of Ln-EDTA complexes with three coordinated water molecules:
[Eu(EDTA−4H)(H2O)3]− moiety is demonstrated in the crystal of NH4[Eu(EDTA−4H)(H2O)3]·5H2O [27];
where Eu (red purple), O (red), N (blue), and C (gray). H atoms, NH4
+ (counter cation), and crystalline water
molecules uncoordinated to Eu3+ are omitted.
Table 1.
Average atomic bond lengths in the crystals of NH4[Ln(EDTA−4H)(H2O)m]·5H2O (m = 3 except for the
cases of m = 2 in both Er). The Eu and Ho have CN = 9, whereas the Er has CN = 8.
NH4-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
63Eu 2.696 2.490 2.420 [27]
67Ho 2.644 2.422 2.365 [28]
68Er(1) 2.558 2.319 2.270 [29]
68Er(2) 2.543 2.316 2.278 [30]
Table 2.
Average atomic bond lengths in the crystals of MA[Gd(EDTA−4H)(H2O)3]·4H2O (MA = CH3NH3;
CN = 9).
Table 1.
Average atomic bond lengths in the crystals of NH4[Ln(EDTA−4H)(H2O)m]·5H2O (m = 3 except for
the cases of m = 2 in both Er). The Eu and Ho have CN = 9, whereas the Er has CN = 8.
NH4-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
63Eu 2.696 2.490 2.420 [27]
67Ho 2.644 2.422 2.365 [28]
68Er(1) 2.558 2.319 2.270 [29]
68Er(2) 2.543 2.316 2.278 [30]
17https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
Table 2.
Average atomic bond lengths in the crystals of MA[Gd(EDTA−4H)(H2O)3]·4H2O (MA = CH3NH3;
CN = 9).
MA-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
64Gd 2.678 2.492 2.412 [31]
Table 3.
Average atomic bond lengths in the crystals of N2H5[Ln(EDTA−4H)(H2O)3]·nH2O (n = 5 except for
the cases of Ce has n = 4, and Eu has n = 3; all have CN = 9).
N2H5-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
58Ce 2.731 2.554 2.471 [32]
59Pr 2.713 2.537 2.454 [33]
60Nd 2.702 2.523 2.440 [33]
62Sm 2.679 2.489 2.415 [33]
63Eu 2.692 2.498 2.419 [32]
64Gd 2.663 2.463 2.395 [34]
65Tb 2.654 2.452 2.385 [34]
66Dy 2.676 2.448 2.371 [35]
Table 4
Average atomic bond lengths in the crystals of Gu[Ln(EDTA−4H)(H2O)3] (Gu = C(NH2)3; all have
CN = 9).
Gu-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
60Nd 2.551 2.506 2.521 [36]
63Eu 2.696 2.661 2.675 [37]
64Gd 2.447 2.400 2.415 [25]
Table 5.
Average atomic bond lengths in the crystals of Gu2[Ln(EDTA−4H)(H2O)2]ClO4·6H2O (Gu = C(N-H2)3;
all have CN = 8).
Gu2-
Ln-ClO4
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
68Er 2.591 2.344 2.275 [38]
70Yb 2.577 2.322 2.254 [39]
71Lu 2.568 2.316 2.245 [25]
18 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
The atomic numbers vs. mean bond dis-
tances (Å) of mononuclear Ln-EDTA com-
plexes are demonstrated in Figure 3. The lan-
thanide contraction phenomenon is obtained;
mean bond distances are gradually reduced
(Ce−Lu). The complexes of CN = 8 (Er−Lu)
have even shorter ion radii than those of CN =
9 (Ce−Ho), possibly explained by reducing the
steric repulsion between the ligands around
the coordination sphere.
Fig. 3. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-OAc), and d(Ln-Ow) vs. atomic numbers
of mononuclear complexes of X[Ln(EDTA−4H)(H2O)m]·nH2O, where X+ = NH4
+, MA+ (= CH3NH3
+),
N2H5
+, and Gu+ (= C(NH2)3
+), in addition to Gu2[Ln(EDTA−4H)(H2O)2]ClO4·6H2O. From Ce to Ho, the
complexes have 9-coordinate geometry (denoted as triangles), whereas from Er to Lu, CN = 8 (circules).
are gradually reduced (Ce−Lu). The complexes of CN = 8 (Er−Lu) have even shorter ion radii than
those of CN = 9 (Ce−Ho), possibly explained by reducing the steric repulsion between the ligands
around the coordination sphere.
Fig. 3. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-OAc), and d(Ln-Ow) vs. atomic numbers of
mononuclear complexes of X[Ln(EDTA−4H)(H2O)m]·nH2O, where X+ = NH4
+, MA+ (= CH3NH3
+), N2H5
+,
and Gu+ (= C(NH2)3
+), in addition to Gu2[Ln(EDTA−4H)(H2O)2]ClO4·6H2O. From Ce to Ho, the complexes
have 9-coordinate geometry (denoted as triangles), whereas from Er to Lu, CN = 8 (circules).
Consequently, the mean bond distances of the complexes of
M[Ln(EDTA−4H)(H2O)m]·nH2O, where M = Na, K, and Cs, are shown in Table 6-8. As mentioned
above, the abbreviation such as Na-La means Na[Ln(EDTA−4H)(H2O)3]·5H2O. These complexes
M[Ln(EDTA−4H)(H2O)m]·nH2O are still thought to be mononuclear, because there are no bridged Ln
ions present. Alkali metal ions, however, are bridged to Ln ions via oxygen atoms (Figure 4). All the
Na-Ln complexes have CN = 9. Among the K-Ln complexes, only one K-Yb complex has
8-coordinate, and others have CN = 9. Cs-Sm and Cs-Gd have 9-coordinate geometry; on the contrary,
Cs-Dy, Cs-Ho, and Cs-Yb have CN = 8. The mean bond lengths vs. atomic numbers of the Ln series
(La–Yb, except for Pm and Tm) with Na, K, and Cs are shown in Figure 5.
Table 6.
Average atomic bond lengths in the crystals of Na[Ln(EDTA−4H)(H2O)m]·nH2O (m = 3, n = 5, except for
the case of n = 3.25 in Dy(3).
Na-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
57La 2.768 2.589 2.493 [24]
Consequently, the mean bond distanc-
es of the complexes of M[Ln(EDTA−4H)
(H2O)m]·nH2O, where M = Na, K, and Cs,
are shown in Table 6-8. As mentioned above,
the abbreviation such as Na-La means Na[L-
n(EDTA−4H)(H2O)3]·5H2O. These complexes
M[Ln(EDTA−4H)(H2O)m]·nH2O are still tho
ught to be mononuclear, because there are no
bridged Ln ions present. Alkali metal ions,
however, are bridged to Ln ions via oxygen
atoms (Figure 4). All the Na-Ln complex-
es have CN = 9. Among the K-Ln complex-
es, only one K-Yb complex has 8-coordinate,
and others have CN = 9. Cs-Sm and Cs-Gd
have 9-coordinate geometry; on the contrary,
Cs-Dy, Cs-Ho, and Cs-Yb have CN = 8. The
mean bond lengths vs. atomic numbers of the
Ln series (La–Yb, except for Pm and Tm) with
Na, K, and Cs are shown in Figure 5.
19https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
Table 6.
Average atomic bond lengths in the crystals of Na[Ln(EDTA−4H)(H2O)m]·nH2O (m = 3, n = 5, except
for the case of n = 3.25 in Dy(3).
Na-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
57La 2.768 2.589 2.493 [24]
58Ce 2.709 2.571 2.491 [40]
59Pr 2.714 2.536 2.458 [19]
60Nd(1) 2.700 2.535 2.451 [24]
60Nd(2) 2.696 2.521 2.454 [36]
62Sm(1) 2.673 2.499 2.423 [24]
62Sm(2) 2.667 2.494 2.421 [41]
62Sm(3) 2.614 2.466 2.381 [42]
63Eu(1) 2.675 2.495 2.411 [24]
63Eu(2) 2.665 2.480 2.410 [43]
64Gd(1) 2.651 2.472 2.399 [19]
64Gd(2) 2.653 2.469 2.400 [44]
65Tb 2.643 2.448 2.377 [43]
66Dy(1) 2.627 2.464 2.392 [18]
66Dy(2) 2.640 2.456 2.377 [43]
66Dy(3) 2.649 2.461 2.381 [45]
67Ho(1) 2.633 2.453 2.363 [22]
67Ho(2) 2.654 2.457 2.395 [46]
68Er 2.618 2.428 2.351 [47]
Table 7.
Average atomic bond lengths in the crystals of K[Ln(EDTA−4H)(H2O)m]·nH2O (m = 3, n = 5, except
for the cases of m = 2 in Yb; n = 3.5 in Eu).
K-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
60Nd 2.712 2.539 2.436 [23]
62Sm 2.692 2.503 2.412 [48]
63Eu 2.677 2.500 2.402 [49]
64Gd(1) 2.677 2.483 2.399 [50]
20 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
64Gd(2) 2.719 2.553 2.464 [51]
65Tb 2.655 2.470 2.390 [52]
67Ho 2.617 2.446 2.367 [47]
70Yb 2.519 2.343 2.272 [53]
Table 8.
Average atomic bond lengths in the crystals of Cs[Ln(EDTA−4H)(H2O)m]·5H2O (m = 3, except for the
cases of m = 2 in both Er).
Cs-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow) d(Ln-OAc)
62Sm 2.671 2.466 2.423 [47]
64Gd 2.654 2.434 2.400 [47]
66Dy 2.574 2.392 2.318 [47]
67Ho 2.584 2.378 2.314 [47]
70Yb 2.532 2.369 2.262 [18]
Table 9.
Average atomic bond lengths in the crystals of [Ln(EDTA−3H)(H2O)m]·nH2O, except for the case of
H-Ce = [Cr(OH)6Mo6O18][Ce3(EDTA−3H)2(H2O)9]·13H2O (CN = 10). From La to Sm: m = 1, n = 0
(La & Ce, CN = 10; Nd & Sm, CN = 9); Gd to Dy(1): m = 0, n = 3; Dy(2) to Er; m = 0, n = 2 (CN = 8).
H-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow)
d(Ln-OAc)
inter intra
57La 2.849 2.655 2.726 2.524 [55]
58Ce 2.789 2.564 2.700 2.504 [56]
60Nd 2.776 2.552 2.453 2.452 [57]
62Sm 2.773 2.548 2.453 2.454 [58]
64Gd 2.626 - 2.354 2.353 [59]
66Dy(1) 2.626 - 2.355 2.354 [61]
66Dy(2) 2.604 - 2.328 2.325 [60]
67Ho 2.592 - 2.323 2.311 [62]
68Er 2.577 - 2.306 2.299 [63]
Table 7.
21https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
Fig. 4. The crystal structures of mononuclear
Na[La(EDTA−4H)(H2O)3]·5H2O [24], where La (red
purple), Na (purple), O (red), N (blue), and C (gray). H
atoms are not shown.
Fig. 4. The crystal structures of mononuclear Na[La(EDTA−4H)(H2O)3]·5H2O [24], where La (red purple),
Na (purple), O (red), N (blue), and C (gray). H atoms are not shown.
Fig. 5. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), and d(Ln-OAc) vs. atomic numbers of
mononuclear complexes of M[Ln(EDTA−4H)(H2O)m]·nH2O, where M+ = Na+, K+, and Cs+. Although K-Yb,
Cs-Dy, Cs-Ho, and Cs-Yb have CN = 8, the remaining complexes have CN = 9.
The complex of Na-Sm(3) has slightly shorter bond distances than that of Na-Sm(1) and
Fig. 4. The crystal structures of mononuclear Na[La(EDTA−4H)(H2O)3]·5H2O [24], where La (red purple),
Na (purple), O (red), N (blue), and C (gray). H atoms are not shown.
Fig. 5. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), and d(Ln-OAc) vs. atomic numbers of
mononuclear complexes of M[Ln(EDTA−4H)(H2O)m]·nH2O, where M+ = Na+, K+, and Cs+. Although K-Yb,
Cs-Dy, Cs-Ho, and Cs-Yb have CN = 8, the remaining complexes have CN = 9.
The complex of Na-Sm(3) has slightly shorter bond distances than that of Na-Sm(1) and
Fig. 5. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), and d(Ln-OAc) vs. atomic numbers of
mononuclear complexes of M[Ln(EDTA−4H)(H2O)m]·nH2O, where M+ = Na+, K+, and Cs+. Although
K-Yb, Cs-Dy, Cs-Ho, and Cs-Yb have CN = 8, the remaining complexes have CN = 9.
The complex of Na-Sm(3) has slightly short-
er bond distances than that of Na-Sm(1) and
Na-Sm(2). For example, does the amount of
crystalline water molecules differ? Wang et al.
(2010) reported an X-ray crystallography with
its approximately consistent elemental analysis
[42]; hence, a possibility of the different com-
position would be incorrect. Conversely, as
22 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
to the case of the K-Gd(2) complex, the bond
distances are irregularly longer compared with
others. By Yang et al. (2002), X-ray crystallo
graphy was the only method for its characteri
zation (both elemental analysis and IR spect
roscopy weren’t reported) [51]. It’s difficult to
say what the deviation would mean, but by
contrast, it should be wondered if the compo-
sition is really accurate in the case of K-Gd(2).
Between Dy and Er, complexes having
CN = 8 and 9 are overlapping. The complex-
es of Cs-Dy and Cs-Ho have CN = 8, whereas
Na-Dy, Na-Ho, Na-Er, and K-Ho have CN = 9.
Compared with 9-coordinate, 8-coordinate
have significantly shorter distances. These facts
seem to indicate that the geometry around the
Ln atoms is influenced by the size and electro-
static properties of the counter-cations accord-
ing to Sakagami et al. (1999) [47]. However,
these findings of the cases of the complexes
having alkali metal ions (M+) are in contrast to
those described for the cases of X+ (NH4
+ and
its analogues such as MA+, N2H5
+, and Gu+) as
counter ions, because in Er, both NH4-Er and
Gu2-Er-ClO4 in spite of having the same 8-co-
ordinate geometry. By manifestation of these
two things, as counter-cations, alkali metals
could have strong perturbation through coor-
dination bonding to the coordination sphere
around the Ln ions than the cases having
NH4
+ and its analogues, not having coordi-
nation bonding to the Ln ions by themselves.
The mean bond distances are reduced from La
to Yb.
Fig. 6. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), d(Ln-OAc-intra), and d(Ln-OAc-intra) vs.
atomic numbers of mononuclear complexes of [Ln(EDTA−3H)(H2O)m]·nH2O, except for the case of
H-Ce = [Cr(OH)6Mo6O18][Ce3(EDTA−3H)2(H2O)9]·13H2O (CN = 10).
Fig. 6. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), d(Ln-OAc-intra), and d(Ln-OAc-intra) vs. atomic
numbers of mononuclear complexes of [Ln(EDTA−3H)(H2O)m]·nH2O, except for the case of H-Ce =
[Cr(OH)6Mo6O18][Ce3(EDTA−3H)2(H2O)9]·13H2O (CN = 10).
In the early study based upon the crystal structure of the H-La complex, its coordination
number had been reported to be CN = 10 [38]. On the other hand, the recent study by Xiong et al.
(2007) reported the CN as 9 [55]. In the present study, the two La3+ are considered to have both CN =
10, including two coordinated intermolecular -COO− groups. The bond lengths of two La-OAc-inter is
2.475 Å and 2.974 Å, respectively; the longer one being considered non-bonding because it is too
long [55].
Among the H-Ln series, a question of the presence or absence of coordinated water
molecules is of interest. In the case of the light rare earths (LRE) from La to Sm, the complexes
exhibit coordinated water molecules, whereas the heavy rare earths (HRE) from Gd to Er do not. As
these series of complexes lack counter-cations such as M+ or X+ (NH4
+ and its analogues), the
intermolecular distances between each H-Ln complex are shortened, resulting in the replacement of
bridging -COO− groups instead of water molecules. This phenomenon is particularly evident in the
complexes of HRE. Furthermore, the transition to CN = 8 is occurring from Gd that is earlier than in
previously discussed monomeric complexes. This distinction would suggest that the H-Ln complexes
should be differentiated from other monomeric one having alkali metal ions, ammonium ions and its
analogues as counter-cations.
Hereafter, the remaining complexes of Ln-EDTA with coordinated water molecules are
discussed whose bond lengths are listed in Table 10. For the cases where Ln ions lacking coordination
with water molecules are also incorporated, only the bond lengths of Ln ions with coordination bonds
23https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
Janicki & Mondry (2014) have summarized
the monomeric [Ln(EDTA−4H)(H2O)n]
− (n =
2, 3, 4) having counter-cations of H+, Na+, K+,
Cs+, NH4
+, and Gu+, where the one having H+
was H[La(EDTA−4H)(H2O)4] [38]. But actu-
ally, it is more appropriate to denote the com-
plex H[La(EDTA−4H)] as [La(EDTA−3H)],
since H+ is on one carboxylate group by Lind
et al. (1965) [54]. Another problem by Janicki
& Mondry (2014) is that the other Ln complex-
es having (EDTA−3H)3− and water molecules
as ligands weren’t discussed [38]. While anoth-
er [Ln(EDTA−3H)] series with crystal struc-
tures had been reported; not as monomeric
complexes but as ones having bridged Ln ions
by oxygen atoms described in Table 9 and Fi
gure 6. Some [Ln(EDTA−3H)] are denoted as
H3O[Ln(EDTA−4H)] in the original articles
[61-63]. Since it should be the -COO− more
basic than water molecules to receive H+, all
compounds are unified as a category within a
series of [Ln(EDTA−3H)] herein.
In the early study based upon the crystal
structure of the H-La complex, its coordina-
tion number had been reported to be CN = 10
[38]. On the other hand, the recent study by
Xiong et al. (2007) reported the CN as 9 [55].
In the present study, the two La3+ are conside
red to have both CN = 10, including two co-
ordinated intermolecular -COO− groups. The
bond lengths of two La-OAc-inter is 2.475 Å and
2.974 Å, respectively; the longer one being con-
sidered non-bonding because it is too long [55].
Among the H-Ln series, a question of the
presence or absence of coordinated water mo
lecules is of interest. In the case of the light rare
earths (LRE) from La to Sm, the complexes
exhibit coordinated water molecules, whereas
the heavy rare earths (HRE) from Gd to Er do
not. As these series of complexes lack coun-
ter-cations such as M+ or X+ (NH4
+ and its ana
logues), the intermolecular distances between
each H-Ln complex are shortened, resulting in
the replacement of bridging -COO− groups in-
stead of water molecules. This phenomenon is
particularly evident in the complexes of HRE.
Furthermore, the transition to CN = 8 is occur-
ring from Gd that is earlier than in previously
discussed monomeric complexes. This distinc-
tion would suggest that the H-Ln complexes
should be differentiated from other monomer-
ic one having alkali metal ions, ammonium
ions and its analogues as counter-cations.
Hereafter, the remaining complexes of
Ln-EDTA with coordinated water molecules
are discussed whose bond lengths are listed in
Table 10. For the cases where Ln ions lacking
coordination with water molecules are also in-
corporated, only the bond lengths of Ln ions
with coordination bonds are demonstrated.
The complexes have somewhat complicated
chemical formulae as follow:
La(1): [La5Cl2(EDTA−4H)3(H2O)18]nCln·8nH2O;
La(2): [La2(SO4)(EDTA−4H)(H2O)3]n;
La(3): K2(NH4)8[La(EDTA−4H)(H2O)2]2[La(cit−3H)(EDTA−4H)]2·22H2O
(cit = citric acid);
La(4): (H2en)[La(EDTA−4H)(H2O)]2·10H2O;
La(5): [{(CH3)2N}2C13H8I]2[{La(EDTA−4H)(H2O)2}2]·4H2O;
La(6): (NH4)5[La3(CO3)(EDTA−4H)3(H2O)3]·12H2O;
La(7): K5[La3(CO3)(EDTA−4H)3(H2O)3]·13.5H2O;
24 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
Ce: K5[Ce3(CO3)(EDTA−4H)3(H2O)3]·13.5H2O;
Pr: H2(PhNHNH2)3[Pr2(EDTA−4H)2(H2O)4]·5H2O;
Nd: [Nd2{o-C6H4(COO)2}(EDTA−4H)(H2O)2]·1.5H2O;
Eu(1): Na[Eu8(EDTA−4H)6(H2O)22]ClO4·28H2O;
Eu(2): Na[Eu9(EDTA−4H)6(H2O)27](ClO4)4·26H2O;
Gd(1): Na[Gd8(EDTA−4H)6(H2O)22]ClO4·28H2O;
Gd(2): Na[Gd9(EDTA−4H)6(H2O)27](ClO4)4·26H2O.
Table 10.
Average atomic bond lengths in the crystal compounds of the Ln-EDTA complexes that have
coordinated water molecules. La(1) to La(5), Pr, and Nd have CN = 10; whereas the remaining
complexes have CN = 9.
H2O-
Ln
Bond length / Å
Ref.
d(Ln-N) d(Ln-Ow)
d(Ln-O)
inter intra
57La(1) 2.821 2.568 − 2.566 [64]
57La(2) 2.785 2.532 2.609 2.612 [64]
57La(3) 2.806 2.650 2.637 2.531 [48]
57La(4) 2.852 2.561 2.643 2.529 [65]
57La(5) 2.833 2.587 2.589 2.539 [66]
57La(6) 2.780 2.529 − 2.535 [67]
57La(7) 2.763 2.529 − 2.534 [67]
58Ce 2.736 2.534 − 2.507 [67]
59Pr 2.796 2.524 2.672 2.475 [68]
60Nd 2.765 2.504 2.615 2.466 [69]
63Eu(1) 2.682 2.497 2.417 2.406 [70]
63Eu(2) 2.680 2.495 2.416 2.409 [70]
64Gd(1) 2.675 2.477 2.401 2.396 [70]
64Gd(2) 2.668 2.483 2.428 2.416 [70]
As displayed in Figure 7, these complexes
with coordinated water molecules have CN =
10 (La−Nd), and CN = 9 (La−Gd). There is a
large overlap between CN = 10 and 9 compared
with the previous shown Ln-EDTA complexes.
The cases of that the proportion of non-major
components except for the lanthanide-cen-
tered EDTA moieties within each complex is
relatively large, it is probable that the coordina-
tion numbers are strongly influenced.
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Daisuke Noguchi UCJ № 09 / Vol. 89
Fig. 7. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), d(Ln-OAc-intra), and d(Ln-O-intra) vs.
atomic numbers of the complicated remaining complexes of Ln-EDTA with coordinated water molecules.
It should be noted that the O atoms in d(Ln-O-intra) are not necessarily belonging to the -COO− in adjacent
EDTA moieties.
63Eu(1) 2.682 2.497 2.417 2.406
[70]
63Eu(2) 2.680 2.495 2.416 2.409
[70]
64Gd(1) 2.675 2.477 2.401 2.396
[70]
64Gd(2) 2.668 2.483 2.428 2.416 [70]
As displayed in Figure 7, these complexes with coordinated water molecules have CN = 10
(La−Nd), and CN = 9 (La−Gd). There is a large overlap between CN = 10 and 9 compared with the
previous shown Ln-EDTA complexes. The cases of that the proportion of non-major components
except for the lanthanide-centered EDTA moieties within each complex is relatively large, it is
probable that the coordination numbers are strongly influenced.
Fig. 7. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-Ow), d(Ln-OAc-intra), and d(Ln-O-intra) vs. atomic
numbers of the complicated remaining complexes of Ln-EDTA with coordinated water molecules. It should
be noted that the O atoms in d(Ln-O-intra) are not necessarily belonging to the -COO− in adjacent EDTA
moieties.
Now that the last remaining series of Ln-EDTA complexes which do not have any
coordinated water molecules are outlined as shown in Table 11 and 12. Here, bond parameters of the
series without coordinated water molecules from Ln-EDTA complexes, which are depicted in Table
10, are also presented. As aforementioned, former studies indicated the lanthanide contraction of
EDTA complexes using only some Ln-EDTA complexes with coordinated water molecules [18-25].
This means that a thorough examination of the lanthanide contraction in EDTA complexes, lacking
coordinated water molecules, is yet to be carried out. Each bond distance is plotted against atomic
Now that the last remaining series of Ln-
EDTA complexes which do not have any coor-
dinated water molecules are outlined as shown
in Table 11 and 12. Here, bond parameters of
the series without coordinated water molecules
from Ln-EDTA complexes, which are depicted
in Table 10, are also presented. As aforemen-
tioned, former studies indicated the lanthanide
contraction of EDTA complexes using only
some Ln-EDTA complexes with coordinated
water molecules [18-25]. This means that a
thorough examination of the lanthanide con-
traction in EDTA complexes, lacking coordi-
nated water molecules, is yet to be carried out.
Each bond distance is plotted against atomic
number for the complexes without coordinat-
ed water molecules in Figure 8. The chemical
formulae for the variety of each compound
are not provided here, however, in some com-
plexes, hydroxide, nitrate, carbonate, peroxide,
phosphite, oxalate, malonate, and citrate ions
are coordinated in place of water molecules or
the O atoms of the -COO− from the neighbor-
ing EDTA anions. In particular, the difference
in bond length surpasses any previous series,
with some bond lengths even practically re-
sembling those of Er complexes with CN = 8,
despite the Ce complex having CN = 10; it is
due to that Ce(4)−Ce(6) have tetravalence;
Ce(IV) [75]. Another characteristic of this se-
ries is the difference in the range of coordina-
tion numbers. The Ln-EDTA complexes with
coordinated water molecules have a CN = 10,
which ranges from La to Nd (also overlapping
26 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
with CN = 9). Conversely, up to Eu, the CN in
the Ln-EDTA complexes without coordinated
water molecules increases to 10. This suggests
that the coordination number of Ln-EDTA
complexes can be significantly tunable while
retaining the EDTA anions as the primary li-
gands.
Table 11.
Average atomic bond lengths in the crystal compounds of the remaining LRE-EDTA complexes that have
no coordinated water molecules; only Sm(1)-EDTA complexes has CN = 9, whereas others have CN = 10.
LRE-EDTA
Bond length / Å
d(Ln-N)
d(Ln-O)
Ref.
inter intra
57La(1) 2.813 2.563 2.588 [71]
57La(2) 2.785 2.563 2.611 [71]
57La(3) 2.802 2.562 2.609 [71]
57La(4) 2.746 2.515 2.657 [64]
57La(5) 2.808 2.568 2.596 [48]
57La(6) 2.803 2.566 2.601 [48]
57La(7) 2.822 2.566 2.650 [72]
57La(8) 2.830 2.573 2.630 [72]
57La(9) 2.771 2.559 2.625 [73]
57La(10) 2.803 2.568 2.593 [73]
57La(11) 2.767 2.556 2.613 [67]
57La(12) 2.768 2.541 2.626 [67]
57La(13) 2.785 2.572 2.581 [67]
58Ce(1) 2.720 2.418 2.342 [74]
58Ce(2) 2.795 2.543 2.568 [71]
58Ce(3) 2.782 2.543 2.595 [71]
58Ce(4) 2.562 2.494 2.317 [75]
58Ce(5) 2.590 2.484 2.316 [75]
58Ce(6) 2.712 2.408 2.331 [75]
58Ce(7) 2.763 2.535 2.597 [73]
58Ce(8) 2.788 2.548 2.578 [73]
58Ce(9) 2.764 2.553 2.566 [67]
58Ce(10) 2.757 2.523 2.618 [67]
62Sm(1) 2.442 2.660 2.432 [48]
62Sm(2) 2.771 2.491 2.482 [76]
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Daisuke Noguchi UCJ № 09 / Vol. 89
Table 12.
Average atomic bond lengths in the crystal compounds of the remaining HRE-EDTA complexes that
have no coordinated water molecules; Eu(3’) have CN = 3, Eu(3), Gd(2), and Gd(4’) have CN = 9, others
have CN = 8.
HRE-EDTA
Bond length / Å
d(Ln-N)
d(Ln-O)
Ref.
inter intra
63Eu(1) 2.748 2.597 2.611 [77]
63Eu(2) 2.793 2.556 2.569 [78]
63Eu(3) 2.755 2.467 2.388 [70]
63Eu(3’) 2.771 2.481 2.501 [70]
64Gd(1) 2.617 2.407 2.308 [79]
64Gd(2) 2.657 2.396 2.421 [79]
64Gd(3) 2.610 2.393 2.319 [79]
64Gd(4) 2.758 2.483 2.595 [79]
64Gd(4’) 2.796 2.434 2.559 [79]
68Er(1) 2.513 2.291 2.343 [80]
68Er(2) 2.574 7.432 2.329 [81]
70Yb(1) 2.553 2.282 2.306 [82]
70Yb(2) 2.539 2.274 2.303 [82]
70Yb(3) 2.533 2.272 2.299 [82]
70Yb(4) 2.541 2.276 2.294 [82]
It is primarily the Ln-O bond lengths that
exhibit the most variation, whereas the Ln-N
bond lengths display comparatively little varia
tion between them. Evidently, factors beyond
the coordinating EDTA anion, such as distinc-
tions in crystal packing due to the kind of co-
ordinating other anions and non-coordinating
moieties, occasionally have an impact on the
atomic bond lengths. This would be because,
in contrast to other rigid ligands, EDTA ani-
ons are flexible. Nonetheless, it is undeniable
that the overall trend towards the lanthanide
contraction is obvious even in this series. From
La to Yb, the average atomic bond lengths are
decreasing.
28 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
Fig. 8. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-O-inter), and d(Ln-OAc-intra) vs. atomic numbers
of the remaining complexes of Ln-EDTA without coordinated water molecules. It should be noted that
the O atoms in d(Ln-O-intra) are not necessarily belonging to -COO− in the neighbouring EDTA moieties.
CONCLUSIONS. In order to achieve a com-
prehensive understanding on the lanthanide
contraction among the complexes of Ln-EDTA
already reported individually, I searched and
analyzed data on 111 kinds of crystal structures
obtained from the CCDC. The finding indi-
cates clear lanthanide contraction in the series
of mononuclear Ln-EDTA complexes with co-
ordinated water molecules having ammonium
ions, its analogues, and alkali metals as coun-
ter-cations. However, there is a tendency for
greater variation in the average atomic bond
lengths as the Ln-EDTA complexes became
non-mononuclear or coordination polymers.
This phenomenon is influenced by various types
of counter-cations, including bridging another
Ln ions coordinated to the O atoms of -COO−
in neighboring EDTA anions, as well as factors
beyond the coordination sphere. Such variation
is uncommon in the studies of the lanthanide
contraction of the complexes having rigid li
gands previously reported. It is suggested that
the EDTA anions have a versatility as ligands,
which could provide a flexibility in the CN and
atomic bond lengths in the lanthanide contrac-
tion. This manuscript is a revised version of my
preprint (doi: 10.51094/jxiv.560).
ACKNOWLEDGEMENTS. I apprecia
te to the CCDC for providing crystal-
lographic data free of charge. I would
also like to acknowledge the fund par-
tially received from the Research Grant
of Nagasaki University for Global
Health Research Collaboration (2023).
Fig. 8. Mean atomic bond distances (Å) of d(Ln-N), d(Ln-O-inter), and d(Ln-OAc-intra) vs. atomic numbers of
the remaining complexes of Ln-EDTA without coordinated water molecules. It should be noted that the O
atoms in d(Ln-O-intra) are not necessarily belonging to -COO− in the neighbouring EDTA moieties.
It is primarily the Ln-O bond lengths that exhibit the most variation, whereas the Ln-N bond
lengths display comparatively little variation between them. Evidently, factors beyond the
coordinating EDTA anion, such as distinctions in crystal packing due to the kind of coordinating other
anions and non-coordinating moieties, occasionally have an impact on the atomic bond lengths. This
would be because, in contrast to other rigid ligands, EDTA anions are flexible. Nonetheless, it is
undeniable that the overall trend towards the lanthanide contraction is obvious even in this series.
From La to Yb, the average atomic bond lengths are decreasing.
CONCLUSIONS. In order to achieve a comprehensive understanding on the lanthanide
contraction among the complexes of Ln-EDTA already reported individually, I searched and analyzed
data on 111 kinds of crystal structures obtained from the CCDC. The finding indicates clear
lanthanide contraction in the series of mononuclear Ln-EDTA complexes with coordinated water
molecules having ammonium ions, its analogues, and alkali metals as counter-cations. However,
there is a tendency for greater variation in the average atomic bond lengths as the Ln-EDTA
complexes became non-mononuclear or coordination polymers. This phenomenon is influenced by
various types of counter-cations, including bridging another Ln ions coordinated to the O atoms of
-COO− in neighboring EDTA anions, as well as factors beyond the coordination sphere. Such
variation is uncommon in the studies of the lanthanide contraction of the complexes having rigid
ligands previously reported. It is suggested that the EDTA anions have a versatility as ligands, which
could provide a flexibility in the CN and atomic bond lengths in the lanthanide contraction. This
manuscript is a revised version of my preprint (doi: 10.51094/jxiv.560).
29https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
КОНТРАКЦІЯ ЛАНТАНІДУ В ХЕЛАТАХ
ЕТИЛЕНДІАМІНТЕТРАОЦТОВОЇ КИСЛОТИ
НА ОСНОВІ КРИСТАЛОГРАФІЧНИХ ДАНИХ:
КОРОТКИЙ ОГЛЯД
Дайсуке Ногучі
Відділ освіти та підтримки досліджень,
Вища школа інженерії, Університет Нага-
сакі,
вул. Бланкйо 1−14, Нагасакі 8528521, Японія
e-mail: a.chemist.noguchi.d@gmail.com
Хоча явище скорочення лантаноїдів
було вже широко вивчено, систематизація
етилендіамінтетраацетату лантаноїду (Ln-
EDTA) залишається недостатньою, хоча
зазвичай використовують хелати EDTA.
Таким чином, це дослідження являє собою
комплексний аналіз на основі даних Кем-
бриджського центру кристалографічних
даних (CCDC). У моноядерних комплексах
EDTA з координованими молекулами води
представлено систематичне скорочення
лантаноїдів залежно від їхнього коорди-
наційного числа. Однак у немоноядерних
комплексах або координаційних полімерах
спостерігаємо більшу варіацію довжини
атомного зв’язку, що є рідкістю для дослі-
джень скорочення лантаноїдів у попередніх
дослідженнях. Це свідчить про гнучкість і
універсальність EDTA як ліганду.
Ключові слова: координаційна сполука,
f-блок, рідкоземельний елемент, поліаміно-
карбонова кислота.
REFERENCES
1. Cotton S.A. Scandium, yttrium & the lantha-
nides: inorganic & coordination chemistry. In:
King RB, Crabtree RH, Lukehart CM, Atwood
DA, Scott RA, editors. Encyclopedia of Inor-
ganic Chemistry: John Wiley & Sons, Ltd. 2006:
1−40.
doi: 10.1002/0470862106.ia211.
2. Pellissier H. Recent developments in enanti-
oselective lanthanide-catalyzed transforma-
tions. Coord Chem Rev. 2017. 336: 96–151.
doi: 10.1016/j.ccr.2017.01.013.
3. Zapolotsky E.N., Qu Y., Babailov S.P. Lantha-
nide complexes with polyaminopolycarbo
xylates as prospective NMR/MRI diagnostic
probes: peculiarities of molecular structure,
dynamics and paramagnetic properties. J Incl
Phenom Macrocycl Chem. 2022. 102(1−2):
1–33.
doi: 10.1007/s10847-021-01112-3.
4. Quadrelli E.A. Lanthanide contraction over
the 4f series follows a quadratic decay. Inorg.
Chem. 2002. 41(2): 167–9.
doi: 10.1021/ic015580v.
5. Seitz M., Oliver A.G., Raymond K.N. The lan-
thanide contraction revisited. J Am Chem Soc.
2004. 129(36): 11153–60.
doi: 10.1021/ja072750f.
6. Jordan R.B. Lanthanide contraction: what is
normal? Inorg Chem. 2023. 62(9): 3715–21.
doi: 10.1021/acs.inorgchem.2c03674.
7. Shannon R.D. Revised effective ionic radii and
systematic studies of interatomic distances in
halides and chalcogenides. Acta Cryst A. 1976.
32(5): 751–67.
doi: 10.1107/S0567739476001551.
8. Cotton S.A. Establishing coordination num-
bers for the lanthanides in simple complexes.
C R Chimie. 2005. 8(2): 129–45.
doi: 10.1016/j.crci.2004.07.002.
9. Cotton S.A., Raithby P.R. Systematics and sur-
prises in lanthanide coordination chemistry.
Coord Chem Rev. 2017. 340: 220–31.
doi: 10.1016/j.ccr.2017.01.011.
30 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
10. Reuter H., Böltken M., Horstmann M., Ha
ase M. Structural evolution in a series of iso-
morphous rare earth compounds as response
of lanthanide contraction. Crystals. 2023.
13(7): 1043.
doi: 1043. 10.3390/cryst13071043.
11. Lu H., Zheng Z., Qiu J., Hou Y., Hou H.,
Wen T., Guo X., Pan Q., Wang Y., Wang J.,
Lin J. Switching photochromism in coordina-
tion polymers by forcing lanthanide contrac-
tion. Cell Rep Phys Sci. 2023. 4(3): 101306.
doi: 10.1016/j.xcrp.2023.101306.
12. Zhang K., Dai Z., Zhang W., Gao Q., Dai Y.,
Xia F., Zhang X. EDTA-based adsorbents for
the removal of metal ions in waste-water. Co-
ord. Chem. Rev. 2021. 434: 213809.
doi: 10.1016/j.ccr.2021.213809.
13. Kolat R.S., Powell J.E. The solid rare earth che-
lates of ethylenediaminetetraacetic acid. Inorg.
Chem. 1962. 1(3): 485–90.
doi: 10.1021/ic50003a008.
14. Porai-Koshits M.A., Polynova T.N. Stereo-
chemistry of metal complexes based on ethy
lenediaminetetraacetic acid and its diamine
analogs. Sov J Coord Chem. 1984. 10(6): 395–
439.
15. Wang J., Hu P., Liu B., Jin X., Kong Y., Gao J.,
Wang D., Wang B., Xu R., Zhang X. Investiga-
tion on coordination number and geometrical
conformation of rare earth complexes with
catenulate aminopolycarboxylic acid ligands.
J Coord Chem. 2010. 63(13): 2193–222.
doi: 10.1080/00958972.2010.500378.
16. Noguchi D. Analysis of specialties of crystal
structure for non-chelate conformations of
ethylene-diaminetetraacetic acid and its salts
with alkali and alkaline earth metals. Ukr.
Chem J. 2022. 88(10): 55–69.
doi: 10.33609/2708-129X.88.10.2022.55−69.
17. Janicki R., Mondry A., Starynowicz P. Carbo
xylates of rare earth elements. Coord. Chem.
Rev. 2017. 340: 98–133.
doi: 10.1016/j.ccr.2016.12.001.
18. Nassimbeni L.R., Wright M.R.W., Niekerk J.
Cvan, McCallum P.A. Packing patterns in
lanthanide–edta complexes: crystal and mo-
lecular structures of sodium triaqua(ethylene-
diaminetetraacetato)dysprosate(III) pentahy-
drate and caesium diaqua(ethylenediamine-
tetraacetato)ytterbate(III) trihydrate. Acta
Cryst B. 1979. 35(6): 1341–5.
doi: 10.1107/S0567740879006415.
19. Templeton L.K., Templeton D.H., Zalkin A.,
Ruben H.W. Anomalous scattering by pra-
seodymium, samarium and gadolinium and
structures of their ethylenediaminetetra
acetate (edta) salts. Acta Cryst B. 1982. 38(8):
2155–9.
doi: 10.1107/S056774088200822X.
20. Stezowski J.J., Hoard J.L. Heavy metal iono-
phores: correlations among structural para
meters of complexed nonpeptide polyamino
acids. Isr J Chem. 1984. 24: 323–34.
doi: 10.1002/ijch.198400055.
21. Ternovaya T.V., Shelest V.P., Gerasimenko
N.V., Ii'nitskaya E.L. Structure of ethylene
diaminetetraacetates of rare-earth elements in
crystals and solutions. Theor. Exp. Chem. 1985.
21(4): 418–28.
doi: 10.1007/BF01004513.
22. Templeton L.K., Templeton D.H., Zalkin A.
Structure of monoclinic sodium (ethylenedi-
aminetetraacetato)holmate(III) octahydrate,
Na[Ho(C10H12N2O8)].8H2O: disorder induced
by radiation. Acta Cryst C. 1985. 41(3): 355–8.
doi: 10.1107/S0108270185003894.
23. Matković-Čalogović D. Structure of potassium
triaqua(ethylenediaminetetraacetato)- neody-
mate(III) pentahydrate. Acta Cryst C. 1988.
44(3): 435–7.
doi: 10.1107/S0108270187011004.
24. Nakamura K., Kurisaki T., Wakita H., Yamagu-
chi T. Sodium triaqua(ethylenediaminetetraac-
etato)lanthanate(III) pentahydrate and the iso-
morphous neodymium(III) and europium(III)
salts. Acta Cryst C. 1995. 51(8): 1559–63.
doi: 10.1107/S0108270195001843.
25. Janicki R., Mondry A. Structural and thermo-
31https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
dynamic aspects of hydration of Gd(III) sys-
tems. Dalton Trans. 2019. 48(10): 3380–91.
doi: 10.1039/C8DT04869J.
26. Noguchi D. Coordination numbers for ra-
re-earths ethylenediaminetetraacetate (REE-
EDTA) in crystalline state: a mini-review. Rep
Grad Sch Eng Nagasaki Univ. 2023. 53(101):
46–53. (in Japanese). Available at
http://hdl.handle.net/10069/0002000111 (acce
ssed December, 2023).
27. Wang J., Zhang X.D., Jia W.G., Zhang Y.,
Liu Z.R. Syntheses and structural research-
es of nine-coordinated (NH4)[EuIII(Edta)
(H2O)3]·H2O and (NH4)3[EuIII(Ttha)]·5H2O.
Russ J Coord Chem. 2004. 30(2): 130–6.
doi: 10.1023/B:RUCO.0000015085.35282.af.
28. Wang X.F., Lui X.Zh., Wang J., Zhang Zh.H.,
Sun W., Kong Y.M., Zhang X.D. Syntheses and
structures of nine-coordinate NH4[HoIII(Edta)
(H2O)3]·1.5H2O, (NH4)4[Ho2
III(Dtpa)2]·9H2O,
and (NH4)3[HoIII(Ttha)]·5H2O complexes.
Russ J Coord Chem. 2008. 34(2): 134–45.
doi: 10.1134/S1070328408020097.
29. Filippova T.V., Polynova T.N., Il'inskii A.L.,
Porai-Koshits M.A., Martynenko L.I. Crystal
structure of the pentahydrate ammonium salt
of erbium(III) ethylenediaminetetraacetate. J
Struct Chem. 1977. 18(6): 895–6.
doi: 10.1007/BF00745486.
30. Polynova T.N., Filippova T.V., Porai-Koshits
M.A. Crystal structure of ammonium erbi-
um(III) ethylenediaminetetraacetate penta
hydrate. Koord Khim. 1985. 12(3): 409–14. (in
Russian).
31. Ma C.C., Li Y., Wang J., Kong D.Y., Qin C.,
Wu Q. Syntheses and structural determination
of mononuclear nine-coordinate (MnH)[GdIII
(EDTA)(H2O)3]·4H2O and 2D ladder-like bi-
nuclear nine-coordinate (MnH)2-[GdIII
2(H2T-
THA)2]·4H2O. Russ J Coord Chem. 2014. 40(9):
617–26. doi: 10.1134/S1070328414080065.
32. Ragul R., Sivasankar B.N. Syntheses, charac-
terization and structural determination of nine
coordinated N2H5[Ce(edta)(H2O)3]·4H2O and
N2H5[Eu(edta)(H2O)3]·4H2O. J Chem Cryst.
2011. 41(9): 1273–9.
doi: 10.1007/s10870-011-0087-6.
33. Ragul R., Sivasankar B.N. Synthesis, structure,
antioxidant, and antiviral studies on N2H5[L-
n(edta)(H2O)3].5H2O (Ln = Pr, Nd, and Sm).
Synth React Inorg Met-Org Nano-Met Chem.
2013. 43(4): 382–9.
doi: 10.1080/15533174.2012.740736.
34. Vikram L., Sonia C., Sivasankar B.N. New
nine coordinated hydrated heavier lanthanide
ethylenediaminetetraacetates containing hyd
razinium cation: molecular structure of
N2H5[Tb(EDTA)(H2O)3]·5H2O and N2H5[G-
d(EDTA)(H2O)3]·5H2O. Asian J Chem. 2013.
25(3): 1441–6.
doi: 10.14233/ajchem.2013.13059A.
35. Vikram L., Sivasankar B.N. New nine coordi-
nated hydrated heavier lanthanide ethylene-
diaminetetraacetates containing hydrazinium
cation: crystal structure of N2H5[Dy(EDTA)
(H2O)3](H2O)5. Indian J Chem A. 2008. 47(1):
25–31. Available at
http://nopr.niscpr.res.in/handle/123456789/
526 (accessed December, 2023).
36. Janicki R., Mondry A. Relationships between
structure and spectroscopic properties of Nd3+
ethylenediaminetetramethylenephosphonates
and ethylenediaminetetraacetates. Eur J Inorg
Chem. 2013. 2013(19): 3429–38.
doi: 10.1002/ejic.201300089.
37. Mondry A., Janicki R. From structural pro
perties of the EuIII complex with ethylene-
diaminetetra(methylenephosphonic acid)
(H8EDTMP) towards biomedical applications.
Dalton Trans. 2006. 39: 4702–10.
doi: 10.1039/B606420E.
38. Janicki R., Mondry A. A new approach to de-
termination of hydration equilibria constants
for the case of [Er(EDTA)(H2O)n]
- complexes.
Phys Chem Chem Phys. 2014. 16(48): 26823–31.
doi: 10.1039/C4CP04093G.
39. Janicki R., Starynowicz P., Mondry A. Com-
plexes of Yb3+ with EDTA and CDTA –
32 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
molecular and electronic structure. Eur J Inorg
Chem. 2008. 2008(19): 3075–82.
doi: 10.1002/ejic.200800249.
40. Drew MG.B., Foreman MR.St.J, Hudson M.J.,
Kennedy K.F. Structural studies of lanthanide
complexes with tetradentate nitrogen ligands.
Inorg Chim Acta. 2004. 357(14): 4102–12.
doi: 10.1016/j.ica.2004.06.032.
41. Engel D.W., Takusagawa F., Koetzle T.F. Neu-
tron diffraction study at 37 K of sodium tri-
aqua(ethylenediaminetetraacetato)sama-
rate(III) pentahydrate, Na[Sm(C10H12N2O8)
(H2O)3].5H2O. Acta Cryst C. 1984. 40(10):
1687–93. doi: 10.1107/S0108270184009173.
42. Wang J., Hu P., Liu B., Chen X., Zhang L.Q.,
Han G.X., Xu R., Zhang X.D. Mononuclear
nine-coordinate Na[SmIII(edta)(H2O)3]·5H2O
and one dimensional unlimited ladderlike
eight-coordinate {[SmIII(Hpdta)(H2O)]·2H2O}n
complexes: synthesis and structural determi-
nation. Russ J Inorg Chem. 2010. 55(10): 1567–
73. doi: 10.1134/S003602361010013X.
43. Holmberg R.J., Korobkov I., Murugesu M.
Enchaining EDTA-chelated lanthanide mole
cular magnets into ordered 1D networks. RSC
Adv. 2016. 6(76): 72510–8.
doi: 10.1039/C6RA09831B.
44. Holmberg RJ, Ho LTA, Ungur L, Korobkov I,
Chibotaru LF, Murugesu M. Observation of
unusual slow-relaxation of the magnetisation
in a Gd-EDTA chelate. Dalton Trans. 2015.
44(47): 20321–5. doi: 10.1039/C5DT04072H.
45. Wang J., Gao G., Zhang Z., Zhang X., Wang Y.
Syntheses and structural determinations
of the nine-coordinate rare earth metal:
Na4[DyIII(dt-pa)(H2O)]2·16H2O,
Na[DyIII (edta)(H2O)3]· 3.25H2O and
Na3[DyIII(nta)2(H2O)]·5.5H2O. J Coord Chem.
2007. 60(20): 2221–41.
doi: 10.1080/00958970701258622.
46. Eggen M., Kędziorski A., Janicki R., Kora
bik M., Krośnicki M. The ab initio and expe
rimental study of the spectroscopic and mag-
netic properties of Ho(III)-EDTA. Polyhedron.
2022. 222: 115851.
doi: 10.1016/j.poly.2022.115851.
47. Sakagami N., Yamada Y., Konno T., Okamo-
to K. Crystal structures and stereochemical
properties of lanthanide(III) complexes with
ethylenediamine-N,N,N′,N′-tetraacetate. In-
org Chim Acta. 1999. 288(1): 7–16.
doi: 10.1016/S0020-1693(99)00005-5.
48. Chen M., Xu Z., Zhou Z. Conversions of mo
nomeric, dimeric and tetrameric lanthanum
and samarium citrates with ethylenediamine-
tetraacetates in aqueous solutions. Polyhedron.
2018. 153: 213–7.
doi: 10.1016/j.poly.2018.07.015.
49. Wang J., Zhang X., Zhang Y., Liu X., Liu Z. Re-
searches on crystal and molecular structures
of nine-coordination mononuclear
K[EuIII(Edta)(H2O)3]·3.5H2O and binucle-
ar K4[EuIII
2(HTtha)2]·13.5H2O. Russ J Coord
Chem. 2004. 30(12): 850–8.
doi: 10.1007/s11173-005-0026-1.
50. Wang J., Zhang X., Fan D., Ling X. Synthesis
and structural determination of nine-coor-
dinate K[GdIII(edta)(H2O)3]·5H2O. Rare Met.
2001. 20(4): 224–9.
51. Yang C., Guo G., Zhou G., Zheng F., Liu J.,
Ma H., Wang M., Huang J. Synthesis and crys-
tal structure of potassium triaqua(ethylenedi-
amine-N,N,N',N'-tetraacetate)gadolinium(III)
pentahydrate. Chin J Struct Chem. 2002. 21(4):
364–7. (in Chinese).
52. Wang J., Liu Z., Zhang X., Jia W., Zhang Y.,
Tong J., Zhang P. Study on syntheses and
structures of nine-coordinated mononuclear
K[TbⅢ(edta) (H2O)3]·5H2O and binuclear
K4[TbⅢ
2(Httha)2]·14H2O complexes. Rare
Met. 2003. 22(4): 241–9.
53. Sakagami N., Homma J., Konno T., Okamo-
to K. Potassium diaqua(ethylenediaminetetra
acetato)ytterbate(III) pentahydrate. Acta Cryst
C. 1997. 53(10): 1376–8.
doi: 10.1107/S0108270197006094.
54. Lind M.D., Lee B., Hoard J.L. Structure and
bonding in a ten-coordinate lanthanum(III)
33https://ucj.org.ua
Daisuke Noguchi UCJ № 09 / Vol. 89
chelate of ethylenediaminetetraacetic acid.
J Am Chem Soc. 1965. 87(7): 1611–2.
doi: 10.1021/ja01085a036.
55. Xiong D., Chen H., Yang X., Zhao J. Hydro-
thermal synthesis and characterization of a
new 1-D polymeric lanthanum ethylenedi-
aminetetraacetate with less metal-aqua coor-
dination: {[La(EDTA)(H2O)]2}n. Inorg Chim
Acta. 2007. 360(5): 1616–20.
doi: 10.1016/j.ica.2006.08.044.
56. Zhang C., Zhang C., Chen Y. Two extended ar-
chitectures formed by Anderson-type polyoxo
metalates and Zr4+/Ce3+–1,2-diaminoethane-
tetraacetate complexes. Solid State Sci. 2011.
13(5): 1122–6.
doi: 10.1016/j.solidstatesciences.2011.01.006.
57. Huang X., Xu X., Pan W., Zeng R. Poly[aqua[μ-
N′-(carboxymethyl)ethylenediamineN,N,N′-
triacetato]neodymium(III)]. Acta Cryst E.
2008. 64(9): m1194.
doi: 10.1107/S1600536808026445.
58. Zhou G., Wu G., Deng Z., Chen X. Poly[aqua[μ3-
N′-(carboxymethyl)ethylenediamine-N,N,
N′-triacetato]samarium(III)]. Acta Cryst E.
2008. 64(10): m1348.
doi: 10.1107/S1600536808031036.
59. Li L., Feng C., Zhang Y. Hydrothermal syn-
thesis, crystal structure and magnetic pro
perties of a new 2D gadolinium(III) complex:
{[Gd(HEDTA)]·3H2O}n. Chin J Inorg Chem.
2011. 27(5): 984–8. Available at http://www.
wjhxxb.cn/wjhxxben/ch/reader/view_ab-
stract.aspx?flag=1&file_no=20110530&jour-
nal_id=wjhxxbcn (accessed December, 2023).
60. Zhuang X., Long Q., Wang J. Poly[[[μ3-N′-(car-
boxymethyl)ethylenediamine-N,N,N′-triace-
tato]dysprosium(III)] trihydrate]. Acta Cryst
E. 2010. 66(11): m1436.
doi: 10.1107/S1600536810041784.
61. You X., Ng S.W. Poly[hydronium [dyspro-
sium(III)-μ3-(ethylenediaminetetraacetato-
κ8N,N′,O,O′,O′′,O′′′:O′′′':O′′′'')] monohydra
te]. Acta Cryst E. 2007. 63(7): m1819.
doi: 10.1107/S1600536807025044.
62. You X., Wang L., Ng S.W. Poly[hydronium
[μ-(ethylenediaminetetraacetato-κ8N,N′,O,
O′,O′′,O′′′:O′′′′,O′′′′′)holmate(III)] monohy-
drate]. Acta Cryst E. 2007; 63(6): m1714.
doi: 10.1107/S1600536807024373.
63. You X., Wang L., Ng S.W. Poly[hydronium
[μ-(ethylenediaminetetraacetato-κ8N,N',O,
O',O'',O''':O'''',O''''')erbate(III)] monohydrate].
Acta Cryst E. 2007. 63(6): m1713.
doi: 10.1107/S1600536807024361.
64. Guo Y., Hou Y., Dong X., Yang Y., Xia W.,
Weng W., Zhou Z. Well-defined lanthanum
ethylenediaminetetraacetates as the precur-
sors of catalysts for the oxidative coupling of
methane. Inorg Chim Acta. 2015. 434: 221–9.
doi: 10.1016/j.ica.2015.05.029.
65. Wang S., Xie Z., Dong X., Zhou Z. Gel self-as-
sembly of lanthanum aminopolycarboxylates
with skeleton structures and adsorptions of
gases. New J Chem. 2021. 45(36): 16816–21.
doi: 10.1039/D1NJ02237G.
66. Chen S., Wang C., Li D., Wang X. Study on
some biologically active coordination com-
pounds of metal ions (I) – synthesis, charac-
terization, structure and antitumor activity of
complex of 3,6-di-(dimethylamino)-dibenzo-
pyriodonium lanthanum EDTA. Sci Chin Ser
B Chem Life Sci Earth Sci. 1989. 32(8): 918–26.
67. Lin R., Shi Y., Hou Y., Xia W., Weng W., Zhou Z.
Highly water-soluble dimeric and trimeric
lanthanide carbonates with ethylenediamine-
tetraacetates as precursors of catalysts for the
oxidative coupling reaction of methane. New
J Chem. 2022. 46(8): 3707–15.
doi: 10.1039/D1NJ05608E.
68. Pradeep R., Naresh K., Hussain T.M.A,
Vikram L., Sivasankar B.N. Crystal and mo-
lecular structure of novel binuclear ten co-
ordinated praseodymium(III) with octaden-
tateethylenediaminetetraacetate – synthesis,
characterization and antioxidant, antiviral and
anticancer activities. J Saudi Chem Soc. 2017.
21(3): 358–65.
doi: 10.1016/j.jscs.2016.11.002.
34 ISSN 2708-129X. Укр. хім. журн., 2023
LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID
BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW.INORGANIC CHEMISTRY
69. Song W., Yan J., Wang H., Ji L., Ma D., Ng S.W.
Hydro(solvo)thermal synthesis and structural
characterization of three lanthanide–carboxy
late coordination polymers based on BDC
and/or EDTA. J Coord Chem. 2010. 63(4):
625–33. doi: 10.1080/00958970903560056.
70. Lu T., Wang X., Cheng L., Chen C., Shi H.,
Zheng J., Zheng X. Soft metal–organic frame-
works based on {Na@Ln6} as a secondary
building unit featuring a magnetocaloric effect
and fluorescent sensing for cyclohexane and
Fe3+. Cryst Growth Des. 2021. 21(12): 7065–74.
doi: 10.1021/acs.cgd.1c00978.
71. Chen M., Gao S., Zhou Z. Isolations and cha
racterization of highly water-soluble dimeric
lanthanide citrate and malate with ethylenedi-
aminetetraacetate. Dalton Trans. 2012. 41(4):
1202–9. doi: 10.1039/C1DT11466B.
72. Wang S., Gao S., Dai J., Shi Y., Dong Y.,
Weng W., Zhou Z. Carbonate and phosphite
encaged in frameworks constructed from
square lanthanum aminopolycarboxylates and
sodium chloride. Dalton Trans. 2019. 48(9):
2959–66. doi: 10.1039/C8DT04940H.
73. Shi Y., Lin R., Chen M., Dong X., Li H.,
Weng W., Zhou Z. Highly water-soluble terna-
ry citrato and malato lanthanide ethylenedi-
aminetetraacetes with carbonate. J Mol Struct.
2022. 1254: 132303.
doi: 10.1016/j.molstruc.2021.132303.
74. Barnes J.C., Blyth C.S., Paton J.D., Smith
I.G.B. Dimeric Ce(IV) peroxide complexes.
Crystal structures of hexapotassium disodi-
um bis-μ-peroxohexacarbonatodicerate(IV)
8-hydrate and dipotassium disodium bis-
μ-peroxobis(ethylenediamine-N,N,N ',N '-
tetraacetato)dicerate(IV) 13-hydrate. Lanth
Act Res. 1990. 3: 181–93.
75. Pook N., Adam A. Synthesis, crystal structure,
and vibrational spectra of five novel peroxi
docerates(IV) and the occurrence of a new
complex unit in K8[Ce2(O2)3(NTA)2]2·20H2O.
Z Anorg Allg Chem. 2014. 640(14): 2931–8.
doi: 10.1002/zaac.201400376.
76. Lu T., Xu H., Cheng L., Wang X., Chen C.,
Cao L., Zhuang G., Zheng J., Zheng X. Family
of nanoclusters, Ln33 (Ln = Sm/Eu) and Gd32,
exhibiting magnetocaloric effects and fluores-
cence sensing for MnO4
–. Inorg Chem. 2022.
61(23): 8861–9.
doi: 10.1021/acs.inorgchem.2c00898.
77. Starynowicz P. Synthesis and structure of tri
sodium (ethylenediaminetetraacetato)europa
te(II) chloride heptahydrate. J Alloys Compd.
1998. 269(1−2): 67–70.
doi: 10.1016/S0925-8388(98)00003-6.
78. Janicki R., Mondry A., Starynowicz P. A new
complex of Europium(II) with edta – structure
and spectroscopy. Z Anorg Allg Chem. 2005.
631(12): 2475–7.
doi: 10.1002/zaac.200500236.
79. Gao S., Chen M., Zhou Z. Substitution of ga
dolinium ethylenediaminetetraacetate with
phosphites: towards gadolinium deposit in
nephrogenic systemic fibrosis. Dalton Trans.
2014. 43(2): 639–45.
doi: 10.1039/C3DT52015C.
80. Gracheva E.V., Vologzhanina A.V., Smirnova
E.S., Tunik S.P. Synthesis and crystal structure
of Na4[Er2(EDTA)2(μ2-C2O4)]·8H2O (where
EDTA stands for ethylenediamine-N,N′-
tetraacetate). Russ J Inorg Chem. 2011. 56(7):
1046–9. doi: 10.1134/S0036023611070072.
81. Janicki R., Mondry A. Structural and thermo-
dynamic aspects of water–carbonate exchange
equilibrium for MIII/IV–EDTA–carbonate sys-
tems. Inorg Chem Front. 2019. 6(1): 153–63.
doi: 10.1039/C8QI01062E.
82. Truong K., Müller P., Dronskowski R., Englert
U. Dynamic uptake and release of water in the
mixed-metal EDTA complex M3[Yb(EDTA)
(CO3)] (M = K, Rb, Cs). Cryst Growth Des.
2017. 17(1): 80–8.
doi: 10.1021/acs.cgd.6b01227.
Cтаття надійшла 01. 09. 2023.
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| id | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-586 |
| institution | Ukrainian Chemistry Journal |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-23T01:10:39Z |
| publishDate | 2023 |
| publisher | V.I.Vernadsky Institute of General and Inorganic Chemistry |
| record_format | ojs |
| resource_txt_mv | ucjorgua/ae/b6e973c2e685b74f7a7c4d0b6b7f5eae.pdf |
| spelling | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-5862026-07-22T08:23:52Z LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW Noguchi, Daisuke coordination compound, f-block, rare-earth element, polyaminocarboxylic acid. The lanthanide (Ln) series has been attracted so much attention not only for its physical properties but also for its applications in organic synthesis and biomedical engineering. In the lanthanide chemistry, lanthanide contraction is a crucial concept meaning the gradual decrease in ionic radii as the atomic number of the Ln series increases. As a prominent chelator, ethylenediaminetetraacetic acid (EDTA) has been well-known to give stable complexes with various metals including Ln ions, resulted in forming (EDTA−4H)4− anion by deprotonation; over 100 kinds of Ln-EDTA complexes have hitherto been synthesized and structurally characterized using X-ray crystallography. While the lanthanide contraction phenomenon has been extensively studied in certain complexes of Ln, systematization on the Ln-EDTA remains inadequate though the chelates of EDTA are commonly used. Thus, this study presents a comprehensive analysis based on the data from the Cambridge Crystallographic Data Centre (CCDC). In mononuclear EDTA complexes X[Ln(EDTA−4H)(H2O)m]·nH2O (X+ = NH4+and its analogues) systematic lanthanide contraction depending on their coordination number are presented except for a few cases. However, in the case of non-mononuclear complexes or coordination polymers, the compositions become more complicated, and a greater variation in atomic bond length occurs, which is unusual for the lanthanide contraction studies in previous research. These varieties are considered to be influenced by different types of counter-cations, inorganic anions, solvent molecules and bridging O atoms from another EDTA anions. This suggests the flexibility and versatility of EDTA as a ligand. Such findings in the Ln-EDTA complexes could potentially provide us further development of a novel function in the future. V.I.Vernadsky Institute of General and Inorganic Chemistry 2023-10-25 Article Article Inorganic Chemistry Неорганическая химия Неорганічна хімія application/pdf https://ucj.org.ua/index.php/journal/article/view/586 10.33609/2708-129X.89.09.2023.14-34 Ukrainian Chemistry Journal; Vol. 89 No. 9 (2023): Ukrainian Chemistry Journal; 14-34 Украинский химический журнал; ##issue.vol## 89 ##issue.no## 9 (2023): Ukrainian Chemistry Journal; 14-34 Український хімічний журнал; Том 89 № 9 (2023): Український хімічний журнал; 14-34 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/586/298 Copyright (c) 2023 Daisuke Noguchi https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Noguchi, Daisuke LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW |
| title | LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW |
| title_full | LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW |
| title_fullStr | LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW |
| title_full_unstemmed | LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW |
| title_short | LANTHANIDE CONTRACTION IN CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID BASED ON CRYSTALLOGRAPHIC DATA: A SHORT REVIEW |
| title_sort | lanthanide contraction in chelates of ethylenediaminetetraacetic acid based on crystallographic data: a short review |
| topic_facet | coordination compound f-block rare-earth element polyaminocarboxylic acid. |
| url | https://ucj.org.ua/index.php/journal/article/view/586 |
| work_keys_str_mv | AT noguchidaisuke lanthanidecontractioninchelatesofethylenediaminetetraaceticacidbasedoncrystallographicdataashortreview |