title: Molecular magnetic properties of two-copper(II) containing complexes [Cu(II) (1-phenylamidino-O-n-butylurea) en (H2O)]2(2+) and [Cu(II) sulphato-mono (1-phenylamidino-O-methylurea)]2. An EPR study.
abstract: Electron paramagnetic resonance (EPR) investigations were conducted on [Cu(II) (1-phenylamidino-O-n-butylurea) en (H2O)]2(2+) (1) and [Cu(II) sulphato-mono (1-phenylamidino-O-methylurea)]2 (2) respectively, in the temperature range 300-77K. Fine structure characteristics of S = 1 system, was observed in both complexes with zero field splitting of 0.0525 and 0.0225 cm(-1), respectively, suggesting the formation of dimeric complexes. The presence of the half-field signal (DeltaMs= +/-2), in the complex 1, further confirmed the formation of dimer. The temperature dependence of EPR signal intensity has given evidence for the ferromagnetic (FM) coupling between the two Cu2+ ions. The isotropic exchange interaction constants J, were evaluated from this and were found out to be approximately 57 and approximately 27 cm(-1), respectively, for the complexes 1 and 2. The photoacoustic spectra of these complexes had shown a band around 26,400 cm(-1) characteristic of metal-metal bonding giving an independent support for the existence of dimeric Cu2+ species. The high magnetic moment values at room temperature for complex 1 (2.68 microB) and complex 2 (2.00 microB), obtained from the magnetic susceptibility measurements, support the formation of ferromagnetically coupled Cu2+ dimers.
authors.affiliation: Department of Chemistry, Manipur University, Imphal 795003, India.
authors.forename: L Ajitkumar
authors.initials: LA
authors.lastname: Sharma
authors.forename: O Ibopishak
authors.initials: OI
authors.lastname: Singh
authors.forename: A K Manihar
authors.initials: AK
authors.lastname: Singh
authors.forename: R K Hemakumar
authors.initials: RK
authors.lastname: Singh
authors.forename: Ramakant M
authors.initials: RM
authors.lastname: Kadam
authors.forename: Madhusudan K
authors.initials: MK
authors.lastname: Bhide
authors.forename: Ashok R
authors.initials: AR
authors.lastname: Dhobale
authors.forename: Medury D
authors.initials: MD
authors.lastname: Sastry
mesh_terms: D003300:Copper / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D008280:Magnetics; D008782:Methylurea Compounds / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014508:Urea / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D008782:Methylurea Compounds; D009942:Organometallic Compounds; D003300:Copper; D014508:Urea