Generation of polymeric cadmium(II) complexes by a flexible double betaine: [{Cd(L)X 2} n] [X = Cl, Br] and [{Cd 2(L)I 4} n [L = meso-2,5-bis(pyridinio)adipate

Abstract

Three polymeric cadmium(II) complexes of a flexible double betaine, namely [{Cd(L)Cl 2} n ] ( 1), [{Cd(L)Br 2} n ] ( 2), [{Cd 2(L)I 4} n ] ( 3) [ L = −O 2 CCH ( C 5 H 5 N +) CH 2 CH 2 CH(C 5 H 5 N +) CO 2 − ] have been prepared and characterized by X-ray crystallography. Complexes ( 1) and ( 2) constitute an isomorphous pair exhibiting a zigzag chain structure running parallel to the c direction, in which Cd II atoms in tetrahedral coordination geometry are cross-linked by double betaine ligands in the unidentate end-to-end mode. Complex ( 3) consists of a two-dimensional polymeric layer composed of a herringbone arrangement of identical 26-membered rings corresponding to the (100) plane, in which the zigzag chains constructed by an alternate arrangement of tetrahedrally coordinated Cd II atoms and bridging iodo ligands are cross-linked by the adipic acid skeletons of the double betaine ligands.