Relationship between the Structure and Nonlinear Optical Properties of R[UO2L3] and R3[UO2L3]4 Crystals (L—Carboxylate Ion)

Abstract

The nonlinear optical activity (Q) of uranyl carboxylates containing [UO₂(L)₃]^– complexes in the crystal structure, where L is the anion of aliphatic or unsaturated monocarboxylic acids, has been characterized for the first time by the second harmonic generation method. It has been shown using molecular Voronoi–Dirichlet polyhedra that specific features of the cationic sublattice of U and R atoms in carboxylate structures depend on noncovalent interactions between outer-sphere R⁺ cations and [UO₂(L)₃]^– complex anions. The existence of a relationship between Q and the magnitude of the vector characterizing the displacement of the uranium atom nucleus from the centroid of its Voronoi–Dirichlet polyhedron in the cation sublattice of U and R atoms is revealed.