Synthesis, X-ray structure, and magnetic properties of di-µ-chloro-bis[N-(2-hydroxy-2-phenylethyl)salicylideneiminatocopper(II)]

Abstract

The crystal and molecular structure of [Cu₂Cl₂L₂]·dmf·H₂O [L =N-(2-hydroxy-2-phenylethyl)salicylideneiminate; dmf = dimethylformamide] has been determined and refined to a final R value of 0.0329 (R′= 0.0257) using 3 979 independent reflections. The dinuclear units crystallize in the monoclinic space group P2₁/c with dimensions a= 8.771(1), b= 13.440(2), c= 29.060(4)Å, and a= 97.113(4)°. Each copper atom is co-ordinated in a distorted square-planar manner by one tridentate Schiff-base anion and one chlorine atom, with normal copper-chlorine distances (mean 2.261 ± 0.002 Å). The chlorine atoms also form long bonds (mean 2.824 ± 0.019 Å) with the second copper atom. The magnetic susceptibilities measured from 5.1 K show a weak antiferromagnetic spin coupling. Fitting of the experimental data by the Bleaney–Bowers equation yielded the parameters g= 2.09(2), 2J₁₂=–7.1(4) cm^–1, and N_α= 131(10)× 10^–6 c.g.s. units. The contribution of intramolecular hydrogen bonds to the overall antiferromagnetic exchange interaction is discussed. The temperature-dependent e.s.r. spectra are reported.