Cobalt(II, III) and copper(II) complexes of 3-(2-furylidene) hydrazino-5,6-diphenyl-1,2,4-triazine

Abstract

A new series of cobalt(II, III) and copper(II) complexes of 3-(2-furylidene) hydrazino-5,6-diphenyl-1,2,4-triazine (L) having formulae LMIIX2, L2MIIX2 and LCoIIIX3, (X = Cl, OAc or ClO4; MII = CoII or CuII) were isolated and characterized by elemental analyses, molar conductances, magnetic moments and i.r., electronic and e.s.r. spectral measurements. The i.r. spectra indicated that the ligand, L, behaves as a neutral bidentate towards divalent metal ions via a triazine-N, and azomethine-N, and acts as a tridentate towards cobalt(III) via the same two nitrogen atoms and the furan-O. The magnetic moments and electronic spectral data suggest a pseudo-tetrahedral geometry for [L2Co]Cl2, a diamagnetic tetragonally distorted octahedral geometry for [LCoCl3], [LCo(OAc)3] · 4H2O and [LCo(H2O)3](ClO4)3 and a dimeric square pyramidal geometry for both [LCuCl2] and [LCu(OAc)2] · 2H2O through bridged chloro and acetato ligands, respectively. The ligand field parameters (B′, 10Dq and β) were evaluated from the electronic spectral data and magnetic moments and related to the bonding of the complexes. The X-band e.s.r. spectra showed three g values with large magnetic anisotropy for [L2Co]Cl2 in accordance with pseudo-tetrahedral CoII complexes; axial pattern for [LCuCl2], [LCu(OAc)2] · 2H2O and [L2Cu(H2O)2](ClO4)2 with two g values and a signal due to ΔMs = ±2 transition for both chloro and acetato copper(II) complexes.