Nickel(II) and copper(II) coordination polymers with 1,2-bis(tetrazol-1-yl)ethane and thiocyanate: Structure, supramolecular isomerism and magnetism

Two heteroleptic coordination polymers with the flexible 1,2-bis(tetrazol-1-yl)ethane (btze) ligand, [Ni(btze)(2)(SCN)(2)](n), (1) and [Cu(btze)(SCN)(2)](n) (2), have been synthesized in presence of thiocyanate. Compound 1 is composed of I D chains with double btze bridges in the V-shaped gauche conformation, while 2 exhibits 2D coordination networks in which 1D chains with double N,S-thiocyanate bridges are crosslinked by btze bridges in the Z-shaped transoid conformation. In both compounds, the coordination motifs are stacked into 3D architectures through S center dot center dot center dot S and C-H center dot center dot center dot N interactions. The structures of 1 and a previously reported compound illustrate an interesting type of supramolecular isomerism. The two isomers exhibit almost identical 1D coordination structure and 2D hydrogen bonded superstructure, and the difference lies only in the interlayer packing associated with S center dot center dot center dot S contacts. Compound 2 exhibits weak antiferromagnetic interactions with J = 0.29 cm(-1), consistent with the structural observation that the thiocyanate bridge adopts an equatorial-axial disposition between Cu(II) ions. (C) 2008 Elsevier B.V. All rights reserved.