CATION EFFECT ON THERMAL STABILITY AND LUMINESCENT PROPERTIES OF BINUCLEAR RARE EARTH ANIONIC COMPLEXES WITH BISCARBACYLAMIDOPHOSPHATE

• Date: 2025
• Main Authors: Kariaka, Nataliia, Trush, Viktor, Amirkhanov, Volodymyr, Fesych, Igor, Gnatyuk, Olena, Gnatyuk, Ivan, Dovbeshko, Galyna
• Format: Article
• Language: English
• Published: V.I.Vernadsky Institute of General and Inorganic Chemistry 2025
• Online Access: https://ucj.org.ua/index.php/journal/article/view/756
• Journal Title: Ukrainian Chemistry Journal

A series of new binuclear anionic coordination compounds of yttrium (III) and europium (III) with bis-carbacylamidophosphate ligand tetramethyl N,N′-(2,2,3,3,4,4-hexafluoro-1,5-dioxo­pentane-1,5-diyl)bis(phosphoramidate) and six different cations has been obtained with an aim to study the cation influence on the thermal and spectral properties of the complexes. The synthesis of coordination compounds was carried out using standard techniques based on the exchange reaction between lanthanide nitrates and the sodium or triethylammonium salt of the ligand in non-aqueous solutions. The complexes’ composition was established by means of elemental and thermal gravimetric analyses as well as 1H NMR spectroscopy. The chelating type of metal bin­ding with participation of both chelating cores of the bis-carbacylamidophosphate was confirmed by IR spectroscopy. It was shown that the cation nature greatly influences the properties of comp­lexes, such as solubility, thermal stability, and luminescence characteristics, as well as determines the degree of the complexes’ hydration. The europium (III) complexes exhibit f-f emission, which is sensitized by the ligands. The luminescence intensity, bands splitting, and bands intensity ratios, as well as luminescence decay time and intrinsic quantum yield, were found to be strongly dependent on the cation in the complexes under study. The red/orange ratio for the europium (III) complexes varies from 2.6 to 7.6, the luminescence decay time varies from 0.76 to 2.74 ms, and the intrinsic quantum yield varies from 24 to 90 %. The temperature of decomposition varies in the range near 155–190 °C, depending on the cation. The manuscript contributes to the studies of influence of outer sphere interactions on the luminescence of lanthanides’ complexes, which is important for design of luminescent compounds with suitable for practical application properties.