Metal chelates of heterocyclic nitrogen containing ketones,Part IX. Magnetic and spectral studies of the dimeric copper(II) complex of 2-picolyl methyl ketone semicarbazone and its ligation by solvent molecules

Summary The preparation and characterization of (PMKSC-H)Cu]₂Cl₂ by i.r. electronic and e.s.r. spectra as well as variable temperature magnetic susceptibility are described and a square planar geometry is assumed for the isolated complex. The magnetic susceptibility data indicates overall antiferromagnetic spin coupling. The variable temperature magnetic susceptibility in conjunction with the best fitting procedure yielded: 2J=–46cm^–1, g=2.15 and 6=–5 K. E.s.r. data confirm the existence of spin-spin coupling with D=0.0398 cm^–1. The g-values obtained from the e.s.r. studies were g₁₁=2.24, g=2.08 and g_av.=2.13. The results were used to estimate the Cu-Cu separation in the dimer. The problem of ligation of the dimeric copper(II) complex by various organic solvents was investigated. E.s.r., i.r. and electronic spectra together with the magnetic susceptibiliy studies indicate that (PMKSC-H)Cu]₂Cl₂ dissociated in polar solvents to give the adducts (PMKSC-H)CuL_s]Cl which were isolated and characterized.