Two new pseudohalide-bridged Cu(II) complexes with a hydrazone ligand: Syntheses, crystal structures and magnetic studies

Two new pseudohalide-bridged copper(II) complexes [{Cu(PBH)(μ1,1-CNO)}2] (1) and {Cu(PBH)(μ1,5-NCNCN)}n (2) (where HPBH = 2-pyridinecarboxaldehyde benzoyl hydrazone) have been synthesised and characterised by elemental analysis, CV, IR and UV–Vis spectral studies. The tridentate hydrazone pro-ligand (HPBH) was obtained by the condensation of benzhydrazide and pyridine-2-carboxaldehyde. Structures of both complexes have been established by X-ray crystallography which shows that 1 is a μ1,1-CNO−-bridged dimer whereas 2 is a μ1,5-dca-bridged (dca = dicyanamide) linear polynuclear structure. Variable temperature magnetic susceptibility studies indicate weak antiferromagnetic interactions with J values −0.50 cm−1 and −0.10 cm−1 for 1 and 2, respectively.

Graphical abstractSynthesis and X-ray single crystal structure determination of two Cu(II) complexes, [{Cu(PBH)(μ1,1-CNO)}2] and {Cu(PBH)(μ1,5-NCNCN)}n have been done. X-ray crystal structure shows the first to be a dimer with the isocyanate ligands bridging in μ1,1 mode, whereas the latter is a double-stranded coordination polymer in which each strand comprises Cu(PBH)+ units linked through μ1,5 bridging dca ligands; the PBH ligands from the two strands alternate in π-stacks parallel to the a axis. Variable temperature magnetic moment studies have been performed and both show antiferromagnetic interaction with J values −0.50 cm−1 and −0.10 cm−1, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide