МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ
New ytterbium (III) compounds with β-diketones (2,7-dimethyl-octene-1-dione-3,5 and 2,6-dimethylheptene-1-dione-3,5) and their derivatives with phenanthroline have been synthesized. The composition and chemical structure of the obtained complexes have been determined by several Physico-chemical inv...
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| Date: | 2021 |
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V.I.Vernadsky Institute of General and Inorganic Chemistry
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Ukrainian Chemistry Journal| _version_ | 1871465681729355776 |
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| author | Ivakha , Nadiia Berezhnytska, Oleksandra Rohovtsov , Oleksandr Rusakova , Nataliia Trunova, Olena |
| author_facet | Ivakha , Nadiia Berezhnytska, Oleksandra Rohovtsov , Oleksandr Rusakova , Nataliia Trunova, Olena |
| author_institution_txt_mv | [
{
"author": "Nadiia Ivakha ",
"institution": "V.I.Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Akad. Palladin Avenue, 32\/34, Kyiv, Ukraine, 03142"
},
{
"author": "Oleksandra Berezhnytska",
"institution": "V.I.Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Akad. Palladin Avenue, 32\/34, Kyiv, Ukraine, 03142"
},
{
"author": "Oleksandr Rohovtsov ",
"institution": "V.I.Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Akad. Palladin Avenue, 32\/34, Kyiv, Ukraine, 03142"
},
{
"author": "Nataliia Rusakova ",
"institution": "O.V.Bohatsky Physico-Chemical Institute of NAS of Ukraine? Lustdorf Road? 86, Odesa, Ukraine, 65000"
},
{
"author": "Olena Trunova",
"institution": "V.I.Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Akad. Palladin Avenue, 32\/34, Kyiv, Ukraine, 03142"
}
] |
| author_sort | Ivakha , Nadiia |
| baseUrl_str | https://ucj.org.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-22T08:23:45Z |
| description | New ytterbium (III) compounds with β-diketones (2,7-dimethyl-octene-1-dione-3,5 and 2,6-dimethylheptene-1-dione-3,5) and their derivatives with phenanthroline have been synthesized. The composition and chemical structure of the obtained complexes have been determined by several Physico-chemical investigations. It has been shown, that the Yb (III) ion coordinates three ligand molecules and the coordination sphere of the complexes is supplemented by two molecules of water or a molecule of phenanthroline. It has been shown that the СN of the ytterbium ion is 8, the coordination polyhedron is a square antiprism, and the complex is characterized by no cubic symmetry. All synthesized compounds exhibit intense IR luminescence. The significant increase in the relative emission intensity of mixed ligand complexes is due to the additional antenna effect of the phenanthroline molecule. |
| doi_str_mv | 10.33609/2708-129X.87.02.2021.65-76 |
| first_indexed | 2025-09-24T17:43:37Z |
| format | Article |
| fulltext |
65
УДК 546.650+547.1’13+541.64+543.426 doi: 10.33609/2708-129X.87.02.2021.65-76
MONO- AND MIXED- LIGAND COMPLEXES OF Yb(III)
WITH NEW β-DIKETONES
N. B. Ivakha1, 2, О. S. Berezhnytska1,2*, О. О. Rohovtsov 1, N. V. Rusakova3, О. K. Trunova1
1 V. I. Vernadsky Institute of General and Inorganic Chemistry of the Ukrainian NAS, prospekt Pal
ladina 32/34, 03142 Kyiv, Ukraine
2 National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», prospekt Pe
remohy 37, 03056 Kyiv, Ukraine
3 A.V. Bogatsky Physico-Chemical Institute of the Ukrainian NAS, 86, Lustdorf road, Odessa 65000,
Ukraine
e-mail: ivakhanadiia@gmail.com
New ytterbium (III) compounds with β-diketones (2,7-dimethyl-octene-1-dione-3,5 and
2,6-dimethyl-heptene-1-dione-3,5) and their derivatives with phenanthroline have been syn-
thesized. The composition and chemical structure of the obtained complexes have been de-
termined by several Physico-chemical investigations. It has been shown, that the Yb (III) ion
coordinates three ligand molecules and the coordination sphere of the complexes is supple-
mented by two molecules of water or a molecule of phenanthroline. It has been shown that
the СN of the ytterbium ion is 8, the coordination polyhedron is a square antiprism, and the
complex is characterized by no cubic symmetry. All synthesized compounds exhibit intense
IR luminescence. The significant increase in the relative emission intensity of mixed ligand
complexes is due to the additional antenna effect of the phenanthroline molecule.
Keywords: β-diketonates, complexes, ytterbium, phenanthroline, luminescent pro
perties.
INTRODUCTION. The regular demand for
new materials with useful applied characteris-
tics primarily gives rise to the rapid develop-
ment of science in the study of compounds with
valuable functional properties. This trend did
not bypass the development of chemistry and
technology of lanthanides (Ln). Until recently,
their field of their application was limited to the
manufacture of pigments for glass and ceramic
coatings, but today it is difficult to imagine a
field of technology that would not use lantha-
nide compounds (including luminescent and
laser materials, elements of catalytic systems,
compounds used in medical practice, etc.) [1, 2].
The permanent expansion of the uses of such
compounds is primarily because more than
half of them can not be fully replaced by
other elements, and Eu, Dy, Tm, and Yb are
unique in their properties. However, the use
of lanthanides in pure form is limited by some
INORGANIC CHEMISTRY MONO- AND MIXED LIGAND COMPLEXES OF Yb(III) WITH NOVEL β-DIKETONES
66 ISSN 2708-129X. Укр. хім. журн., 2021
disadvantages [3], so the development of re-
search on the chemistry of coordination com-
pounds of rare earth elements (REE) comes to
the fore. Probably, the most promising feature
of lanthanide complexes is their ability to lumi-
nescence, as the presence of narrow emission
bands characteristic of each ion can provide
not only the purity of the emission color but
also quite high values of REE luminescence
intensity in complexes with many organic li
gands. Among them, there are β-diketones,
because such chelate complexes are characte
rized by a set of valuable properties important
for practical use [4].
The least attention in modern research is
devoted to lanthanide complexes that emit
in the near IR region of the spectrum (Nd
(III), Er (III), Yb (III)). Note that among the
known complexes with the above metals, the
Yb (III) ion has a higher quantum efficiency
and a longer lifetime of luminescence with a
wavelength of about 1000 nm [5,6], which is
important for use in biological objects, because
they are transparent in this range. Therefore,
the study of Yb (III) complexes is of practical
interest.
It is known, that the coordination number in
lanthanide complexes is usually more than six,
and in some cases can reach 12, so it is almost
impossible to obtain coordinatively saturat
ed complexes with branched β-diketones [7].
In this case, the coordination sphere of the lan-
thanide ion is supplemented by solvent mol-
ecules, which may adversely affect the final
characteristics of the obtained compound. For
example, it is known that the presence of wa-
ter molecules in the first coordination sphere
of the complex leads to the loss of a signifi-
cant part of the energy for the excitation of
high-frequency oscillations of -OH groups and
the subsequent nonradiative relaxation. One of
the ways to overcome this problem is to obtain
mixed ligand complexes with neutral donor
molecules with the simultaneous displacement
of solvent molecules. The best known of these
is 1,10-phenanthroline (Phen) because it has
high absorption capacity and efficient energy
transfer to the central ion. This approach al-
lows one not only to minimize the influence of
luminescence quenching molecules but also to
purposefully change the final characteristics of
the compound, such as solubility and thermal
stability.
Despite the rather extensive experimental
material accumulated for the synthesis and
study of β-diketonate complexes of lantha
nides, including those emitting in the IR re
gion, many aspects remain undiscovered and
need further study to establish correlations
between the structure of organic ligands and
properties.
Thus, taking into account the prospects
of this area of research, the synthesis of Yb
(III) coordination compounds with 2,7-di-
methyl-octene-1-dione-3,5, and 2,6-dime-
thyl-heptene-1-dione-3,5 and mixed ligand
phenanthroline complexes based on them was
carried out in the work. The spectral, thermal
and luminescent characteristics of the obtained
compounds were studied.
EXPERIMENT AND DISCUSSION OF RE
SULTS. Sodium salts of β-diketones 2,7-di
methyl-octene-1-dione-3,5 and 2,6-dime
thyl-heptene-1-dione-3,5 were synthesized by
Kleisen condensation according to the method
described in [8] (Table 1).
UCJ № 2 / Vol. 87N. B. Ivakha, О. S. Berezhnytska, О. О. Rohovtsov, N. V. Rusakova, О. K. Trunova
67https://ucj.org.ua
Table 1. – Structural formulas and name of β-diketonate ligands.
formula Name abbreviation
O OH
2,6-dimethyl-heptene-1-dione-3,5 Hdmhpd
O OH
2,7-dimethyl-octene-1-dione-3,5 Hdmod
The purity of the synthesized unsatura
ted β-diketones was determined by elemental
analysis and the 1H NMR method [9].
The synthesis of complexes of Yb (III) with
dmhpd, dmod was performed by the interac-
tion of aqueous solutions of ytterbium chlo-
ride (YbCl3∙6H2O, AR grade) with an aqueous-
ethanolic solution of a sodium salt of the
corresponding ligand at a molar ratio of 1: 3.5
(pH 8–8.5) at room temperature.
Yb3+ + 3NaL →YbL3 + 3Na+
L = dmhpd, dmod
The resulting precipitates of the complexes
were separated from the mother liquor by cen-
trifugation, washed five times with deionized
water, and dried in a vacuum desiccator over
anhydrous CaCl2. The synthesized complexes
based on both β-diketones are amorphous pale
yellow powders.
The synthesis of mixed ligand complexes
(MLCs), in which phenanthroline was used as
the second ligand, was performed in alcohol
solutions at a ratio of LnL3: Phen = 1: 1. The
solutions were left for 3–5 h to establish equi-
librium and to carry out the reaction of com-
plexation. The precipitated complexes were fil-
tered off and washed with ethanol.
YbL3·2H2O + Phen → YbL3·Phen + 2H2O
L= dmhpd, dmod
The synthesized compounds were charac-
terized by IR spectroscopy, diffuse reflectance
spectroscopy, thermogravimetry and lumines-
cence analysis.
The hydrate composition of the complexes
and their thermal characteristics were deter-
mined by the DTA method. The thermograms
were recorded on a derivatograph Q–1500°D
of the system F. Paulik, J. Paulik, L. Erdey in the
temperature range of 20–500°С with a heating
rate of 5°С/min. in a platinum crucible in the
presence of a carrier (anhydrous Al2O3).
The IR spectra were recorded on a Specord
M80 spectrometer in the range of 400–4000
cm-1 in KBr pellets.
The diffuse reflection spectra in the range of
300–1100 nm were recorded on a UV-VIS-IR
Shimadzu UV–3600 spectrophotometer.
The excitation and luminescence spectra
of the solid complexes were recorded on a
spectrofluorimeter Fluorolog FL 3–22, Hori-
ba Jobin Yvon (Хe-lamp 450 W) using a light
filter. InGaAs (DSS-IGA020L, Electro-Optical
Systems, Inc, USA) photoresistance at liquid
nitrogen temperature was used as a radiation
receiver for the IR region.
INORGANIC CHEMISTRY MONO- AND MIXED LIGAND COMPLEXES OF Yb(III) WITH NOVEL β-DIKETONES
68 ISSN 2708-129X. Укр. хім. журн., 2021
Information on the composition and me
thod of coordination of the synthesized β-dike
tonate complexes was obtained based on the
analysis of results by IR spectroscopy and ther-
mogravimetry. Based on the literature [10],
the classification of the characteristic bands of
oscillations in the IR spectrum of the studied
samples was carried out (Table 2). The comp
lexation is evidenced by the absence of intense
oscillation bands at 1700–1750 cm-1, which cor-
respond to ν(C=O) of free β-diketone, and the
appearance of characteristic oscillation bands
in the region of higher energies in the range of
1520–1600 cm-1, which correspond to the os-
cillations of the one and a half bonds νas(СС),
νs(СО), which indicates the bidentate-cyclic co-
ordination of ligands to the metal ion.
Also in the range of 400–600 cm-1 there is a
set of bands that corresponds to a combination
of valence oscillations of the Yb–O bond and
deformation oscillations of the chelate ring,
and in the case of phenanthroline complexes a
band corresponding to the valence oscillation
of Yb–N additionally appears. Their presence
also confirms the formation of both monoli-
gand and mixed ligand complexes.
In the region of 890–720 cm-1 there is a set
of bands, among which in the spectra of mixed
ligand complexes oscillation frequencies at
775 and 778 cm-1 can be distinguished, which
correspond to the band of deformation oscilla-
tions of CH bonds of the phenanthroline frag-
ment (free phenanthroline – 779 cm-1). The ν
oscillation band of the C – N group, which is
observed for pure phenanthroline at 1560 cm–1,
overlaps with the intense bands νas(СС),
νs(СО), so it is not possible to identify them.
For the hydrated complexes of ytterbium
with dimethylheptenedione and dimethy-
loctendione in the range of 3200–3600 cm-1,
a wide oscillation band of OH groups is ob-
served, which is due to the presence of wa-
ter molecules in the complexes. In the case
of phenanthroline complexes, the absence of
this band proves that such complexes are an-
hydrous, and, consequently, the phenanthrolin
molecule is coordinated to the Yb (III) ion.
Table 2 – Assignment of oscillation frequencies in the IR spectra of the synthesized comp
lexes (cm-1)
Compound ν(Ln–O) +
δchel.ring ν(Ln–N) νas (СС) νs (СО) ν (C=O) ν (C=C)
Nadmhd – – 1565 – 1724 1655
Nadmod – – 1558 – 1715 1645
Yb(dmhpd)3⋅2H2O 420, 431, 498, 518 – 1537 1581 – 1671
Yb(dmhpd)3⋅Phen 418, 435, 481, 524 471 1545 1596 – 1670
Yb(dmod)3⋅2H2O 425, 445, 489, 514 – 1541 1586 – 1669
Yb(dmod)3⋅Phen 424, 450, 495, 520 469 1549 1591 – 1671
UCJ № 2 / Vol. 87N. B. Ivakha, О. S. Berezhnytska, О. О. Rohovtsov, N. V. Rusakova, О. K. Trunova
69https://ucj.org.ua
The hydrate composition and the heat resist-
ance of the synthesized compounds were de-
termined by a thermogravimetric analysis. The
first endoeffect on thermograms appears in the
range of 97–145°C for Yb(dmhpd)3⋅2H2O and
115–158°C for Yb(dmod)3⋅2H2O, which cor-
responds to the dehydration of complexes, in
particular to the loss of two coordinated water
molecules, the weight loss is 5.5 and 5.0 wt%
for Yb(dmhpd)3 and Yb(dmod)3, respectively,
which is consistent with the theoretically cal-
culated value. Slight exoeffect at 258°C for Yb
(dmhpd)3⋅2H2O, 260°C for Yb(dmhpd)3⋅Phen,
288°C and 269°C for Yb(dmod)3⋅2H2O and
Yb(dmod)3⋅Phen, respectively, probably corre-
sponds to the melting point of the complexes. In
the same interval, the polymerization of unsatu
rated β-diketonate complexes can occur without
an initiator, consequently, we observe the super-
position of several processes on each other.
Further increase in temperature is accom-
panied by a sharp increase in the rate of weight
loss and exoeffects in the range of 320–455°C,
which corresponds to the decomposition of the
organic part of the complexes. It should be not-
ed that depending on the nature of the complex-
es (mono- and heteroligand) there may be dif-
ferent mechanisms of decomposition, which is
due to the presence of donor molecules of phe-
nanthroline in the molecules of heteroligand
complexes. For the correct recording of thermo-
grams in the range of 200–500°C it is necessary
to research without access to air to reduce the
probability of formation of oligomeric forms of
metal complexes. Obviously, the complexes de-
compose to ytterbium oxide (III), the shape of
the curve indicates the sublimation of the com-
plexes during the study.
Table 3 – Thermal analysis of ytterbium complexes
compound
Phen The process of dehydration tdestuction,oС
Δm, % t, oС/ thermo
effect
Δm, %
n(H2O) tstart. tfin.calc. found calc. found
Yb(dmhpd)3⋅2H2O – – 145/еndo 5,4 5,5 2 312 475
Yb(dmhpd)3⋅Phen 22,1 25,8 89/еndo adsorbed – 355 477
Yb(dmod)3⋅2H2O – – 152/еndo 5,1 5,0 2 328 462
Yb(dmod)3⋅Phen 21,1 24,1 91/еndo adsorbed – 334 455
Thus, according to the results of thermal
analysis and IR spectroscopy, it was found that
the first coordination sphere of diketonate com-
plexes Yb (III) includes two water molecules,
which are completely replaced by a phenan-
throline molecule in the case of mixed ligand
compounds, and that the composition corre-
sponds to the formulas Yb(β-dik)3∙2H2O and
Yb(β-dik)3∙Phen (β-dik = dmhpd, dmod).
It is known that for the organic molecules
which contain unsaturated groups absorp-
tion in the near ultraviolet (200–400 nm) and
visible (400–800 nm) regions is associat
ed with π → π * or n → π * transitions [11].
INORGANIC CHEMISTRY MONO- AND MIXED LIGAND COMPLEXES OF Yb(III) WITH NOVEL β-DIKETONES
70 ISSN 2708-129X. Укр. хім. журн., 2021
Therefore, the analysis of the intensity of the
bands and changes in their position in the
electronic spectra in this range can be useful for
the structure determination of the molecule.
In the diffuse reflection spectra (Fig. 1a)
of the synthesized β-diketonates of ytterbi
um in the region of 200–350 nm, an extended
band is observed (with maxima at 285 nm for
Yb(dmhpd)3·2H2O and 288 nm for Yb(dmоd)3
·2H2O), which can be assigned to the electronic
π→π * transitions from the basic (S0) to the ex-
cited state (S1) of ligand molecules. In the case
of phenanthroline derivatives of the obtained
complexes, there is abroadening, splitting into
two components and hypsochromic shift of
this band (λmax = 222, 265 nm and λmax = 225,
269 nm for the complexes with dmhpd and
dmod, respectively), which indicates the coor
dination of the molecule of phenanthroline to
the lanthanide ion and, consequently, the super-
position of π→π* transition bands and the band
of charge transfer from the ligand to the metal.
As is known, in the electronic spectra for all
Ln3+ ions are characterized by the presence of
strictly defined characteristic bands that corre-
spond to the f-f transitions of lanthanide ions
from the ground state. It is known that the Yb3+
ion has only one multiplet term 2F, which cor-
responds to 4f-electrons [12].
Due to the spin-orbit interaction, the compo-
nents of this term 2F5/2 and 2F7/2 are distant from
each other, which is manifested by the charac-
teristic Yb3+ transitions in the near IR region of
the spectrum in the range of 975–985 nm, in the
so-called «therapeutic window of tissue trans-
parency». For Yb(III) complexes, we observe
only one broadened split into 2 components
transition with a maximum at ~ 980 nm. The
rather wide shoulder in the region of the main
transition, which is in the range of 920–930
nm is due to the only allowed transition for Yb
(III), the significant emission capacity of the yt-
terbium ion in this coordination environment
and, possibly, non-radiative processes. λmax for
the transition 2F7/2 →
2F5/2 of ytterbium ion in
the studied samples is 971 nm (Yb(dmhpd)3
·2H2O), 972 nm (Yb(dmоd)3·2H2O), 974 nm
(Yb(dmhpd)3·Phen) and 972 nm (Yb(dmоd)3·
Phen) (Fig. 1, b). Whereas the maxima corre-
sponding to the π→π ∗ transitions undergo a
significant shift (2700–3000cm-1) upon the in-
sertion of an additional ligand, which is due to
changes in the energy state of the coordination
compounds owing to the coordination of the
additional molecule of phenanthroline, the line
shape and maximum position of the single su-
persensitive transition 2F7/2 →
2F5/2 not only do
not shift, but also do not change the shape and
Figure 1 – SDR complex Yb(dmhpd)3·2H2O, Yb(dmhpd)3·Phen, Yb(dmоd)3·2H2O and Yb(d-
mоd)3·Phen.
UCJ № 2 / Vol. 87N. B. Ivakha, О. S. Berezhnytska, О. О. Rohovtsov, N. V. Rusakova, О. K. Trunova
71https://ucj.org.ua
intensity, which indicates a similar structure of
the coordination polyhedron in all synthesized
coordination compounds of ytterbium.
Thus, the analysis of the diffuse reflection
spectra allows us to conclude, that the struc-
ture of the coordination node does not under-
go significant changes upon the formation of
both mono- and mixed ligand complexes, the
coordination number of the Yb3+ ion for all
synthesized complexes is 8, and the shape of
the coordination polyhedron corresponds to
a square antiprism, as in previously presented
studies [13]. The much lower band intensity
for the dimethyloctenedione-based monoli-
gand complex can be explained by the fact that
the central ion is shielded with the increasing
length of the substituent in the β-diketonate
fragment. We observed a similar situation in
the case of bulk phenolic substituents. Unfor-
tunately, it is impossible to determine the cor-
relations of this effect with IR spectra as to the
length of bonds and the influence of substitu-
ents on them due to the presence in the range
of 400–700 cm-1 of some oscillations charac-
teristic not only of the M-O bond but also of
metal cycle oscillation.
Since the replacement of two molecules of
water (a) by a molecule of phenanthroline (b)
in the coordination sphere of complexes prac-
tically does not lead to changes in the geom-
etry of molecule. The structure of complexes
can be schematically represented as follows.
R=-CH(CH3)2 (dmokd), -CH(CH3) (dmhpd), -C6H5 (mphpd)
As noted above, OH oscillations significantly
reduce the luminescence intensity for the ele-
ments of several lanthanides. However, it should
also be noted that for the Nd (III), Er (III), and
Yb (III) ions a significant contribution to the
probability of non-radiative transition is made
by the oscillations of CH groups, so it is impor-
tant to synthesize compounds that could pro-
vide the «rigidity of the frame» of the obtained
complexes and thus minimize their negative
impact. In [14, 15] it is noted that the elements
of the end of the lanthanide series (including
the Yb (III) ion) are characterized by the forma-
tion of mixed ligand complexes with the most
rigid coordination sphere, which, in turn, rules
out the possibility of formation of several types
of molecules and has a positive effect on their
final characteristics. From this point of view, the
synthesis of MLCs with branched ligands is also
an extremely promising direction in coordina-
tion chemistry.
For lanthanide ions emitting in the IR re-
gion of the spectrum, there are to date insuf-
ficient data on the optimal value of the energy
gap between the triplet levels of ligands and
the emitting levels of Ln (III) ions. Accord-
INORGANIC CHEMISTRY MONO- AND MIXED LIGAND COMPLEXES OF Yb(III) WITH NOVEL β-DIKETONES
72 ISSN 2708-129X. Укр. хім. журн., 2021
ing to Dexter’s theory [16], this difference is
an extremely important factor for the mani-
festation of effective emission, and both too
large and too small gap between the energies
of the ligand and the metal can lead to a de-
crease in radiation intensity. It is known, that
the resonance level of the ion Yb (III) is quite
low (2F5/2–10330 cm-1), besides, there are no
energy levels near it to which the excitation
energy could be transmitted, so the determin-
ing factor, in this case, is the energy value of
the triplet level of the ligand. To calculate the
values of the triplet levels of dimethylhepten-
edione and dimethyloctenedione, gadolinium
complexes were synthesized and their fluores-
cence and phosphorescence spectra (at 77 K)
were recorded. This allowed us calculating ET
dmhpd (21000 cm-1) and ET dmod 19350 cm-
1). The energy values of the triplet levels are
higher than the energy of the emitting level of
the Yb(III) ion, which indicates the potential
for intramolecular energy transfer to the metal
ion and the ability to show effective 4f-lumi-
nescence by such complexes.
Based on these data, a study of the lumines-
cent properties of all synthesized monoligand
and mixed ligand complexes of ytterbium with
phenanthroline was performed. It is appropri-
ate to compare the luminescent properties of the
synthesized complexes with aliphatic substitu-
ents (dmhpd, dmod) and aromatic (mphpd)
[17, 18] in the molecule of β-diketone. The
emission excitation spectra of the powders
(Fig. 2, a) of the synthesized complexes con
sist of one band split into two components with
maxima λ1max = 322–323 nm and λ2max = 365–
367 nm, respectively. At the same time, the ex-
citation spectrum of Yb(mphpd)3 consists of a
wide diffuse band with a maximum at 340 nm.
Therefore, emission spectra were recorded at
different excitation wavelengths. When excited
with the maximum of these bands, an intense
4f-luminescence is observed in all cases.
The emission spectra of all ytterbium comp
lexes contain one broadened band that corre-
sponds to the transition from the excited lev-
el of the Yb (III) ion 2F5/2 → 2F7/2 (Fig. 2, b).
As can be seen from the figure, this band for
Yb(dmhpd)3 is the most broadened and split
into 3 maxima. For Yb(dmod)3, the emission
curve is also quite wide, which allows it to be
decomposed into 3 components, but the main
maximum of the band is of much higher in-
tensity. However, the relative luminescence
intensity of Yb(mphpd)3 is 6 times lower than
that of Yb(dmhpd)3 and 13 times lower than
for Yb(dmod)3. The difference in the shape and
relative intensity of the bands is due to the dif-
Figure 2 – Emission spectra of Yb(ІІІ)3 with other ligands, Т=293К, λзб.= 323 nm.
UCJ № 2 / Vol. 87N. B. Ivakha, О. S. Berezhnytska, О. О. Rohovtsov, N. V. Rusakova, О. K. Trunova
73https://ucj.org.ua
ferent nature of the substituents in the β-diket-
onate fragment. The reason for the broadened
lines is a decrease in the symmetry of the co-
ordination polyhedron, the exchange interac-
tions, and the peculiarity of the luminescence
of ytterbium compounds. The coordination
number remains unchanged, as evidenced by
the increase in the relative intensity of lumines-
cence. The lower luminescence intensity of the
complex with aromatic substituent (mphpd)
is due to the steric factor, in particular to the
shielding of the emitting centers by bulky mol-
ecules. Comparing compounds with aliphatic
substituents, we observe that with the increas-
ing length of substituent per methylene group
the emission intensity increases by a factor
of 2, the maximum band shifts by 2 nm, but
the shape and line width are the same, which
may indicate the similar symmetry and coor-
dination polyhedra of these complexes. Pre-
sumably, the presence of an additional -CH2-
group, due to the redistribution of electron
density, weakens the bond of the Yb(III) ion to
the ligand and, as a consequence, contributes
to more efficient energy transfer from the li-
gand to the metal; in addition, of all calculated
energies of triplet levels, ЕТdmod is lowest.
The expected results in terms of increas-
ing emission intensity in mixed ligand com-
plexes came true. Comparison of the relative
luminescence intensity of phenanthroline
complexes (Fig. 3) showed that adding a do-
nor molecule Phen stimulates an increase in
emission intensity by a factor of 3.5 for the
compounds with aliphatic substituent (dmh-
pd) and in 8 with aromatic substituent (mph-
pd), and that the position of the band shifts by
6 nm. This is due to the steric effect, the possi-
bility of stacking interaction of aromatic sys-
tems (phenanthroline and phenolic substit-
uent in the ligand molecule), and the higher
symmetry of methacroylacetophenoate com-
plexes. Also, for mixed ligand complexes, we
observe a narrowing of the line by a factor of
2, which may indicate a decrease in nonradi-
ative transitions and suggests an increase in
the symmetry of the complexes (Fig. 4). The
presence of two maxima in the emission ex-
citation spectrum prompted us to record the
emission spectra at different excitation wave-
lengths. It was established that for all mixed
ligand complexes the optimal excitation
wavelength is 360 nm, at the same time for
monocomplexes it is 320 nm.
Figure 3 – Emission spectra of complexes of
Yb(ІІІ)3 with phenantroline, Т=293К, λзб.= 360 nm.
Figure 4 – Emission spectra of complexes
Yb(dmhpd)3·2H2O and Yb(dmhpd)3·Phen, Т=293К
at different wavelengths of exitation.
INORGANIC CHEMISTRY MONO- AND MIXED LIGAND COMPLEXES OF Yb(III) WITH NOVEL β-DIKETONES
74 ISSN 2708-129X. Укр. хім. журн., 2021
CONCLUSIONS. For the first time, mono-
and mixed-ligand complexes of ytterbium
(III) based on dimethylheptene and dimethyl
octenedione were synthesized in this work. The
composition and structure of the synthesized
complexes has been determined. It has been
shown that the ligand molecules are coordi-
nated to the central ion in a bidentate-chelate
fashion. The C.N. of the central ion of ytterbi-
um is 8. In the case of monoligand complexes,
the coordination sphere is supplemented by two
molecules of water. It has been shown that all
synthesized coordination compounds exhibit
intense emission in the near IR region of the
spectrum. The addition of the second ligand to
the molecules causes an increase in the relative
emission intensity, which is due to the replace-
ment of water molecules in the near coordi-
nation environment of the central ion, which
caused the quenching processes. A comparative
analysis of the properties of the synthesized
complexes with aliphatic substituents and com-
plexes based on methacroylacetophenone has
been performed. The highest emission intensity
of the synthesized complexes based on dmod
is due to the linear structure of the substituent
and, accordingly, to the lack of its shielding ef-
fect, which occurs in the case of methacroylace-
tophenone and to the lower triplet level energy
of the ligand, which reduces the energy gap be-
tween ETligand and ES (Yb), which, in turn, reduces
the amount of non-radiative loss. Thus, all syn-
thesized compounds can be used as precursors
of luminescent materials.
The research was performed within
the framework of departmental topics
318 E "Creation of new multifunction-
al nanomaterials based on coordina-
tion compounds of 3d-metals and lan-
thanides with O, N-donor ligands"
МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ
Yb(III) З НОВИМИ β-ДИКЕТОНАМИ
Н. Б. Іваха1,2*, О. С. Бережницька1,2,
О. О. Роговцов1, Русакова Н. В.3,
О. К. Трунова1
1 Інститут загальної та неорганічної хімії
ім. В. І. Вернадського НАН України,
просп. Академіка Палладіна, 32/34, Київ
03142, Україна
2 Національний технічний університет Ук
раїни “Київський політехнічний інститут”
імені Ігоря Сікорського, просп. Перемоги, 37,
Київ 03056, Україна
3 Фізико-хімічний інститут ім. О. В. Богат
ського НАН України, Люстдорфська дорога,
86, Одеса 65000, Україна
e-mail: ivakhanadiia@gmail.com
У роботі синтезовано нові сполуки ітер-
бію(ІІІ) з β-дикетонами (2,7-диметил-ок-
тен-1-діоном-3,5 і 2,6-диметил-гептен-1-ді-
оном-3,5) та їхні змішанолігандні похідні з
фенантроліном. За допомогою низки фізи-
ко-хімічних досліджень отриманих комп-
лексів встановлено їхній склад та хімічну
будову. В ІЧ-спектрах синтезованих коор-
динаційних сполук спостерігають набір
смуг, який вказує на бідентатно-циклічну
координацію лігандів до іону металу. Смуги
в інтервалі 400–600 см-1 відповідають ком-
бінації валетних коливань зв’язку Yb–O та
деформаційних коливань хелатного кіль-
ця, а у випадку фенантролінових комп-
лексів додатково проявляється смуга, що
відповідає валентному коливанню Yb–N.
Дослідження термічної стійкості зразків
дозволили встановити, що координаційна
UCJ № 2 / Vol. 87N. B. Ivakha, О. S. Berezhnytska, О. О. Rohovtsov, N. V. Rusakova, О. K. Trunova
75https://ucj.org.ua
сфера монолігандних комплексів доповню-
ється двома молекулами води, які повністю
витісняються молекулою фенантроліну у
змішанолігандних аналогах. Форма, поло-
ження та зміщення спектральних смуг в
ЕСДВ свідчить про проходження процесів
комплексоутворення та одержання комп-
лексів некубічної симетрії з к. ч. Yb (ІІІ) 8.
Входження молекули фенантроліну до
складу комплексів суттєво не впливає на
будову координаційного вузла. Досліджен-
ня методом люмінесцентного аналізу пока-
зали, що всі одержані сполуки проявляють
інтенсивну люмінесценцію в ІЧ-області
спектру, причому слід зазначити, що на-
явність додаткової -СН2- групи у випадку
комплексів із dmod сприяє підвищенню
відносної інтенсивності емісії. Синтез змі-
шанолігандних комплексів також збільшує
ефективність випромінювання внаслідок
нівелювання негативного впливу О–Н-ко-
ливань молекул води, тому всі представлені
сполуки можна запропонувати як прекур-
сори люмінесцентних матеріалів.
Ключові слова: β-дикетонати, комплек-
си, ітербій, фенантролін, люмінесцентні
властивості.
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Стаття надійшла 19.03.2021.
|
| id | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-276 |
| institution | Ukrainian Chemistry Journal |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-23T01:05:54Z |
| publishDate | 2021 |
| publisher | V.I.Vernadsky Institute of General and Inorganic Chemistry |
| record_format | ojs |
| resource_txt_mv | ucjorgua/11/9c090ee9f5b8e6343afd1ad685a94511.pdf |
| spelling | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-2762026-07-22T08:23:45Z MONO- AND MIXED- LIGAND COMPLEXES OF Yb(III) WITH NEW β-DIKETONES МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ Ivakha , Nadiia Berezhnytska, Oleksandra Rohovtsov , Oleksandr Rusakova , Nataliia Trunova, Olena β-diketonates, complexes, ytterbium, phenanthroline, luminescent properties. New ytterbium (III) compounds with β-diketones (2,7-dimethyl-octene-1-dione-3,5 and 2,6-dimethylheptene-1-dione-3,5) and their derivatives with phenanthroline have been synthesized. The composition and chemical structure of the obtained complexes have been determined by several Physico-chemical investigations. It has been shown, that the Yb (III) ion coordinates three ligand molecules and the coordination sphere of the complexes is supplemented by two molecules of water or a molecule of phenanthroline. It has been shown that the СN of the ytterbium ion is 8, the coordination polyhedron is a square antiprism, and the complex is characterized by no cubic symmetry. All synthesized compounds exhibit intense IR luminescence. The significant increase in the relative emission intensity of mixed ligand complexes is due to the additional antenna effect of the phenanthroline molecule. V.I.Vernadsky Institute of General and Inorganic Chemistry 2021-03-19 Article Article Inorganic Chemistry Неорганическая химия Неорганічна хімія application/pdf https://ucj.org.ua/index.php/journal/article/view/276 10.33609/2708-129X.87.02.2021.65-76 Ukrainian Chemistry Journal; Vol. 87 No. 2 (2021): Ukrainian Chemistry Journal; 65-76 Украинский химический журнал; ##issue.vol## 87 ##issue.no## 2 (2021): Украинский химический журнал; 65-76 Український хімічний журнал; Том 87 № 2 (2021): Український хімічний журнал; 65-76 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/276/153 Copyright (c) 2021 Nadiia Ivakha , Oleksandra Berezhnytska, Oleksandr Rohovtsov , Nataliia Rusakova , Olena Trunova https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Ivakha , Nadiia Berezhnytska, Oleksandra Rohovtsov , Oleksandr Rusakova , Nataliia Trunova, Olena МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ |
| title | МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ |
| title_alt | MONO- AND MIXED- LIGAND COMPLEXES OF Yb(III) WITH NEW β-DIKETONES |
| title_full | МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ |
| title_fullStr | МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ |
| title_full_unstemmed | МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ |
| title_short | МОНО- ТА ЗМІШАНОЛІГАНДНІ КОМПЛЕКСИ Yb(III) З НОВИМИ β-ДИКЕТОНАМИ |
| title_sort | моно- та змішанолігандні комплекси yb(iii) з новими β-дикетонами |
| topic_facet | β-diketonates complexes ytterbium phenanthroline luminescent properties. |
| url | https://ucj.org.ua/index.php/journal/article/view/276 |
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