Effect of the metal ion radius on the structure of SrII—ZnII and SrII—CdII complexes with cyclobutane-1,1-dicarboxylate anions

Strontium(II)—zinc(II) and strontium(II)—cadmium(II) coordination compounds with dianions of cyclobutane-1,1-dicarboxylic acid (H 2 cbdc) were synthesized. In the complexes [Sr 4 Zn 4 (cbdc) 8 (H 2 O) 9 ] n (1) and {[SrCd(cbdc) 2 (H 2 O) 3 ] · 3H 2 O} n (2) , the cyclobutane-1,1-dicarboxylate dianions are coordinated to strontium atoms in a chelate fashion to form monomeric mono- and bischelate moieties, which link the d-metal atoms into a polymer structure. An increase in the ion radius of the d-metal in going from zinc(II) to cadmium(II) is accompanied by a decrease in the dimensionality of the coordination polymer from layered to chain.