A Facile Direct Synthesis of Bimetallic Cu II Zn II Complexes with Ethylenediamine Revealing Different Types of Chain Crystal Structures

Unactivated copper metal powder and zinc oxide readily react with ethylenediamine (en) in nonaqueous [methanol, dimethylformamide (dmf), dimethyl sulfoxide (dmso), acetonitrile] solutions of ammonium salts under ambient conditions producing, in high yields, a series of heterobimetallic complexes of general formula [Cu(en) 2 ZnX 4 ]·(Solv), where X = Cl, Br, NCS, CH 3 COO (OAc); Solv = dmf, dmso, CH 3 CN, H 2 O. The single‐crystal X‐ray analysis of the complexes reveals chain structures, which are based on the completion of the octahedral coordination of Cu II by two bridging X atoms from ZnX 4 2− . The ZnX 4 2− is shown to be a distorted tetrahedron (Cl, Br, NCS) or a very distorted octahedron (OAc) and to behave as a one‐ or two‐linking centre bridging ligand. The chains are found to be zigzag [Cu(en) 2 ZnCl 4 ]·dmso ( 1 ), [Cu(en) 2 ZnCl 4 ]·dmf ( 2 ), [Cu(en) 2 Zn(NCS) 4 ]·CH 3 CN ( 3 ), quasi linear [Cu(en) 2 Zn(OAc) 4 ] ( 4 ), or helical, [Cu(en) 2 Zn(NCS) 4 ]· 0.5H 2 O ( 5 ), depending on the nature of the anion and solvent. Complex 4 represents the first compound containing Zn(OAc) 4 2− to be crystallographically authenticated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)