title: Electron spin resonance and magnetic studies on some copper(II) azobarbituric and azothiobarbituric acid complexes.
abstract: Electron spin resonance and magnetic susceptibility on some copper(II) complexes prepared from phenylazobarbituric and phenylazothiobarbituric acid compounds containing 2,5-dichloro and 2,5-dimethyl groups were discussed. The thio complexes exist in dimer-monomer mixture. The corresponding copper(II) complexes of the oxygen homologous failed to exhibit association. Singlet-triplet separation values equal to -321 and -263 cm(-1) for the 2,5-dimethyl and 2,5-dichloro complexes, respectively, of the thio series. An empirical measure of the amount of tetrahedral deformation based on the values of g||/A|| assigned the square-planar geometry of the dimethyl-oxygen complex while the other complexes are with tetrahedral planar geometries. The effect of temperature on the ESR data was discussed. The diamagnetic properties of the complexes derived from 2,5-dichloro and 2,5-dimethyl thiobarbituric acid suggested the formation of Cu(I) complexes.
authors.affiliation: Chemistry Department, Faculty of Science, Alexandria University, Egypt. drmsmasoud@yahoo.com
authors.forename: M S
authors.initials: MS
authors.lastname: Masoud
authors.forename: E A
authors.initials: EA
authors.lastname: Khalil
authors.forename: A M
authors.initials: AM
authors.lastname: Hafez
authors.forename: A F
authors.initials: AF
authors.lastname: El-Husseiny
mesh_terms: D003300:Copper / Q000737:chemistry*; D003627:Data Interpretation, Statistical; D004578:Electron Spin Resonance Spectroscopy; D008280:Magnetics; D013858:Thiobarbiturates / Q000737:chemistry*
chemical_list: D013858:Thiobarbiturates; D003300:Copper