title: X-ray, spectral and biological (antimicrobial and superoxide dismutase) studies of oxalato bridged CuII-NiII and CuII-ZnII complexes with pentamethyldiethylenetriamine as capping ligand.
abstract: X-band electron spin resonance (ESR) and electronic spectra of oxalatobridged heterodinuclear Cu-Ni and Cu-Zn complexes, viz., [(PMDT)Cu-Ox-Ni(PMDT)](BPh(4))(2).2CH(3)CN and [(PMDT)Cu-Ox-Zn(PMDT)](BPh(4))(2).2CH(3)CN, where PMDT=pentamethyldiethylenetriamine, Ox=oxalate ion have been described. Complex [(PMDT)Cu-Ox-Ni(PMDT)](BPh(4))(2).2CH(3)CN has been structurally characterized. This complex crystallizes in the monoclinic space group, C(2) (No. 5) with the unit parameters a=20.445(4) A, b=14.884(3) A, c=23.174(5) A, alpha=90 degrees, beta=102.693(4) degrees, gamma=90 degrees, V=6880(2) A(3) and Z=4. The structure refined to R=0.0354 and R(w)=0.0853 for 21,109 reflections with I>2 sigma(I) using 765 parameters, shows the presence of a MN(3)O(2) chromophore in a distorted trigonal-bipyramidal (TBP) heterometallic complex with oxalate dianion. Taking with an equatorial Cu-O=2.137(8) A and an axial Cu-O=1.961(6) A coordination site at Cu(II) ion and equatorial Ni-O=2.178(7) A and axial Ni-O=1.994 (9) A coordination site at Ni(II) ion. The Cu-Ni distance is 5.3532(9) A and Cu-C(2)O(4)-Ni unit is planar. The [(PMDT)Cu-Ox-Ni(PMDT)](2+) shows the ESR spectrum of the antiferromagnetic spin exchange with each dinuclear delocalization of the unpaired electron over the unit and spin-doublet ground state which demonstrates the Cu-Ox-Ni core. Antimicrobial and superoxide dismutase (SOD) activities of these complexes have also been measured.
authors.affiliation: Department of Chemistry, A.P.S. University, Rewa 486 003, Madhya Pradesh, India. rnp64@yahoo.co.uk
authors.forename: R N
authors.initials: RN
authors.lastname: Patel
authors.forename: Nripendra
authors.initials: N
authors.lastname: Singh
authors.forename: K K
authors.initials: KK
authors.lastname: Shukla
authors.forename: U K
authors.initials: UK
authors.lastname: Chauhan
authors.forename: S
authors.initials: S
authors.lastname: Chakraborty
authors.forename: J
authors.initials: J
authors.lastname: Niclós-Gutiérrez
authors.forename: A
authors.initials: A
authors.lastname: Castiñeiras
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D003300:Copper / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D019216:Metals, Heavy / Q000737:chemistry / Q000378:metabolism; D009532:Nickel / Q000737:chemistry / Q000378:metabolism; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D010070:Oxalates / Q000737:chemistry / Q000378:metabolism; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship; D013482:Superoxide Dismutase / Q000378:metabolism*; D015032:Zinc / Q000737:chemistry / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D019216:Metals, Heavy; D009942:Organometallic Compounds; D010070:Oxalates; D003300:Copper; D009532:Nickel; D013482:Superoxide Dismutase; D015032:Zinc