Synthesis and Characterization of Anionic Lanthanide(III) Complexes with a Bidentate Sulfonylamidophosphate (SAPh) Ligand
A series of new anionic lanthanide(III) complexes with the general formula NEt4[LnL4] (1-Ln; HL = dimethyl[(4-methylphenyl)sulfonyl]amidophosphate; Ln = La, Nd, Eu), were synthesized and characterized by IR, UV-vis, and NMR spectroscopies, the differential scanning calorimetry method, thermogravimetric and X-ray analysis, and photoluminescence measurements. Single-crystal structures of NEt4[EuL4] (1-Eu) were determined at 293 and 100 K and evidenced the single-crystal-to-single-crystal phase transition. Both phases are in the monoclinic crystal system in centrosymmetric groups of the same Laue class. The room temperature structure is in C2/c (No. 15), while low-temperature structure is in the P21/c (No. 14) space groups. The coordination environment geometry around the central europium(III) ion is a distorted square antiprism in both polymorphs, while the peripheral methoxy and tolyl groups show different orientations. This phenomenon indicates the occurrence of a thermally driven second-order phase transition during the cooling-heating process. The europium(III) complex exhibits an unusual emission spectrum, clearly dominated by the 5D0-7F4 bands, and an emission decay time equaling 3.5 ms, being among the highest values known for europium coordination compounds.
Olyshevets, Iryna, Nataliia Kariaka, Kateryna Znovjyak, Nikolay Gerasimchuk, Sergey Lindeman, Sergii Smola, Maksym Seredyuk, Tetiana Yu Sliva, and Vladimir M. Amirkhanov. "Synthesis and characterization of anionic lanthanide (III) complexes with a bidentate sulfonylamidophosphate (SAPh) ligand." Inorganic chemistry 59, no. 1 (2018): 76-85.