Two novel 2D cadmium compounds with noncentrosymmetric or symmetric network dependent on different pH values

Abstract

Hydrothermal reaction of cadmium chloride and 2-carboxyethyl(phenyl)phosphinic acid (H2L) under pH 2.69 or 5.00 afforded two novel Cd(II) compounds with the formula of [Cd(HL)2]n (I) and [Cd3(L)2(OH)2]n (II), respectively. Both compounds were well characterized by elemental analysis, IR spectroscopy, power X-ray diffraction, fluorescence and single-crystal X-ray diffraction (CIF files CCDC nos. 1049809 (I), 1049810 (II)). Compound I crystallizes in a Pca21 space group and presents a two-dimensional (2D) layered noncentrosymmetric structure, in which slight difference of the two Cd–O(phosphinico) distances leads to the formation of the chiral phosphorus atom in HL– ligand. Compound II adopts a centrosymmetric P21/c space group and exhibits a 2D network. Both compounds show violet fluorescence, assigned as an intraligand emission.