COMPUTATIONAL STUDY ON THE STRUCTURE AND PROPERTIES OF TERNARY COMPLEXES OF Ln3+ (Ln = La, Ce, Nd and Sm) WITH 5,7-DICHLOROQUINOLINE-8-OL AND 4-VINYL PYRIDINE

ion imprinting lanthanide complexes density functional theory polarized continuum model conformational distribution

Кристаллическая структура 4,4?-динитро-[3,3?:4?,3?]-трис-[1,2,5]-оксадиазола, КРИСТАЛЛИЧЕСКАЯ СТРУКТУРА ДВУХ ПОЛИМОРФНЫХ МОДИФИКАЦИЙ ТИОБРОМИДА НИОБИЯ NbS2Br, ...

For VP and DCQ ligands, the cation binding energy sequence follows the order La3+ > Ce3+ > Nd3+ > Sm3+ as expected based on increasing in the hardness and decreasing in the ionic radius of this lanthanide cation series. <...> A similar trend was observed in the calculated binding energy of the aforesaid ligands with the hydrated lanthanide cation series [Ln(H2O)9]3+, while the computed values of deformation energy of ligands upon complexation demonstrated an opposite order in the lanthanide cation series. <...> Moreover, the solvent effects are considered via a polarized continuum model and provided a significant increase in the binding strength while the relative magnitude of binding energies is the same as that in the gas phase. <...> Combining quantum and statistical mechanical calculations, we have also determined quantitatively a reliable estimate of the conformational distribution of the [Sm(VP)2(DCQ)3]3+ complex at various temperatures in the gas phase by computing the molecular partition functions and consequently the analysis of the conformational equilibrium constants. <...> Keywords: ion imprinting, lanthanide complexes, density functional theory, polarized continuum model, conformational distribution. <...> Schematic representation of ligands: 4-vinyl pyridine (VP) and 5,7dichloroquinoline-8-ol (DCQ) plate in a highly cross-linked polymer matrix. <...> It should be noticed that there are many reports on the lanthanide ion imprinted polymer preparation [ 4—6 ]especially during the past years, which describe a preconcentrative separation of lanthanide cations by co-polymerizing [Ln(VP)2(DCQ)3]3+ ternary complexes, styrene and a cross linker, e.g. divinyl benzene, in the presence of 2,2-azo bis isobutylonitrile as an initiator. <...> In the present investigation, we shall concentrate on the quantum chemistry calculation of intrinsic interactions of lanthanide cations Ln3+ with DCQ and VP ligands from the structural and energetic viewpoints. <...> In addition to ion—ligand interactions, solvation plays an important role in the ion imprinting process. <...> Furthermore, because of the strong electrostatic character of the metal—ligand interactions, which remains effective beyond the first and even second coordination sphere, structural parameters are sensitive to the solvent effect. <...> So, we have also estimated solvent effects on the structure and binding energies of ligands in [Ln(VP)2(DCQ)3]3+ complexes by concerning a continuum representation <...>

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