Synthesis, characterization and magnetochemical studies of some copper(II) complexes derived from n-salicylidene- n-alkanoylhydrazins: X-ray crystal and molecular structure of bis [monochloro-(μ- n-salicylidenemyristoylhydrazine)ono(−1)] dicopper(II)

Abstract

Three types of copper(II) complexes, [Cu(HL)Cl · H 2O] · xH 2O, [{Cu(HL)Cl} 2] and [{Cu(L)} 2], derived from N-Salicylidene- n-alkanoylhydrazines (H 2L) have been synthesized and characterized by elemental analyses, infrared spectra and field desorption mass spectra as well as variable temperature magnetic susceptibility measurements. The X-ray molecular structure of bis[monochloro(μ- N-salicylidene myristoylhydrazine)ONO ′(−1)]dicopper(II) showed that this complex is a centrosymmetric dimer in which each copper(II) is in a distorted square pyramidal environment and coordinated in the equatorial plane to the ONO mononegative tridentate acylhydrazone ligand. The fourth coordination site is occupied by the symmetry related phenoxy oxygen of the other monomeric unit. The chloride ion occupies the fifth axial coordination site. Magnetic susceptibility measurements at different temperatures (5–298 K) showed that the hydrated chloro complexes [Cu(HL)Cl · H 2O] · xH 2O are monomeric and no spin–spin interaction was detected, while the anhydrous chloro complexes [{Cu(HL)Cl} 2] are dimeric and exhibit strong antiferromagnetic coupling with −2 J values the range 466–477 cm −1. The neutral complexes [{Cu(L)} 2] also show antiferromagetic behaviour with −2 J varying from 170 to 243 cm −1.