A NEW CYANO-BRIDGED ONE-DIMENSIONAL POLYMERIC MIXED-VALENCE CU-II CU-I COMPLEX FORMED FROM REDUCTION OF A BINUCLEAR CU-II COMPLEX WITH SODIUM-CYANIDE/

A new cyano-bridged polymeric mixed-valence Cu-II/Cu-I complex, [Cu(di en)(2)(CN)(2)Cu(CN)](n) (2) (dien = diethylenetriamine) has been prepa red by the partial reduction of the OH-bridged binuclear complex [Cu-2 (dien)(2)(OH)](ClO4)(3) (1) with sodium cyanide. The X-ray crystal str ucture shows that 1 is a polymeric, linear mixed-valence Cu-I/Cu-II co mplex and consists of a one-dimensional three-coordinated [Cu-I(CN)](n ) chain, in which the Cu-I atoms are linked by two disordered CN bondi ng groups. The structure of each Cu-II atom consists of a square-pyram idal five-coordinate environment, in which the basal plane is formed b y the three nitrogen atoms of the dien ligands and one carbon atom of the terminal cyanide group, and the apical position is occupied by the nitrogen atom of a bridging cyano ligand. This is the first example o f one Cu-II centre coordinating with two different bonding types of th e terminal Cu-II-CN and the bridging Cu-II-NC in a polymeric complex. The cryomagnetic behaviour has been investigated in the temperature ra nge 4.2-300 K. There is a weak antiferromagnetic interaction between t wo intrachain copper(II) ions with J= -0.47 cm(-1). (C) 1997 Elsevier Science Ltd.