title: Synthesis, physico-chemical and spectral investigations of novel homo-bimetallic mixed-ligand complexes: 57Fe Mössbauer parameters of [Fe2(imda)2(H2O)3Cl].
abstract: The newly prepared homo-bimetallic complexes [M(2)(imda)(2)(H(2)O)(4)], [M(2)(imda)(2)(Bipy)(2)] (M=Co, Ni or Cu) and [Fe(2)(imda)(2)(H(2)O)(3)Cl] (H(2)imda=iminodiacetic acid and Bipy=2,2'-bipyridine) have been studied employing IR, FAB-mass, (1)H and (13)C NMR, EPR and ligand field spectra, which indicated a high-spin state of metal ion with hexa-coordinate environment. (57)Fe Mössbauer data of the homo-bimetallic complex [Fe(2)(imda)(2)(H(2)O)(3)Cl] confirm a high-spin configuration with Fe (+/-3/2-->1/2) nuclear transitions and the presence of Kramer's double degeneracy. At RT, the spin-spin interactions of the neighbouring nuclei (Fe(3+)-Fe(3+)=S(5/2)-S(5/2)) are anti-ferromagnetically coupled. However, at LNT, the complex acquires a mixed-valent [Fe(III)-Fe(II)] composition corroborated from the X-band EPR data. CV studies indicated the presence of quasi-reversible redox Cu(II/I), Cu(II/III), Fe(III/II), Fe(III/I) and Fe(II/I) couples.
authors.affiliation: Division of Inorganic Chemistry, Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India. zafarasiddiqi@yahoo.com
authors.forename: Zafar A
authors.initials: ZA
authors.lastname: Siddiqi
authors.forename: M
authors.initials: M
authors.lastname: Shahid
authors.forename: Mohd
authors.initials: M
authors.lastname: Khalid
authors.forename: Shabana
authors.initials: S
authors.lastname: Noor
authors.forename: Sarvendra
authors.initials: S
authors.lastname: Kumar
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D015204:Spectroscopy, Mossbauer / Q000379:methods*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D005290:Ferric Compounds; D008024:Ligands; D008670:Metals