The Use of Trans-4-cotininecarboxylate to Construct a Polymeric Copper(II) Azido Complex: Hydro(solvo)thermal Synthesis, Structure and Magnetic Properties

A new pyridyl-carboxylate ligand, the anion of trans-4-cotininecarboxylic acid, HL, 1, has been used to prepare a new polymeric copper(II) complex, [CuLN 3] 2n, 2, based on a [CuLN 3] 2 dimeric building block. The single crystal structures of both 1 and 2 have been determined and 1 has been found to be in its zwitterionic configuration. The structure of 2 is a one-dimensional tape-like polymeric structure based on an end-on azido-bridged binuclear [Cu 2N 3] 2 backbone moiety. Magnetic studies reveal that 2 is close to paramagnetic from 2 to 300 K with a Curie constant of 1.094 emu K/mol, a Weiss temperature of 0.73 K and a corresponding μ eff of 2.09 μ B. A fit of χ MT for 2 with S 1 = S 2 = , yields g = 2.441(6), J = -0.49(3) cm -1, zJ = -0.38(2) cm -1 and N(α) = 0.00053(12) emu/mol, a fit that indicates the presence of both very weak intramolecular intrachain antiferromagnetic exchange coupling within the one-dimensional tape-like chains and very weak interchain antiferromagnetic exchange coupling between these chains. © 2010 Elsevier B.V. All rights reserved