title: Synthesis, electronic structure, and structural characterization of the new, "non-innocent" 4,5-dithio-catecholate ligand, its metal complexes, and their oxidized 4,5-dithio-o-quinone derivatives.
abstract: The bifunctional ligand catechol-4,5 dithiol, H(2)Dtcat, has been synthesized, and the structure of the bis Br(-) adduct, (HS)(2)C(6)H(2)(OH)(2).2Ph(4)Br.H(2)O, has been determined. The syntheses, molecular structures, electronic structures, and magnetic properties of the monoanionic [(Dtcat(2-))(2)M](-), (M = Ni, V and M = Cu, VI) complexes have been obtained as Ph(4)PBr double salts, [M(S(2)C(6)H(2)(OH)(2))(2)][Ph(4)P](3)Br(2). These and the antiferromagnetically coupled dimeric [(Dtcat)(2)Fe][Ph(4)P](2).4DMF complex, VII, have been structurally characterized. The centrosymmetric [M(S(2)C(6)H(2)(OH)(2))(2)](-) complexes in the X-ray isomorphous V and VI are connected via H-bonding to Br(-) ions to form one-dimensional chains well separated from each other by the Ph(4)P(+) cations. Magnetic measurements show V to be a S = 1/2 and VI a S = O molecules. The distribution of electrons in these compounds have been determined by density functional theory calculations which show V to be a radical anion Ni(II) complex and VI a partially oxidized-ligand, reduced-copper complex. The 4,5 dithio-o-quinone [(Dtoq)(2)Ni][Ph(4)P](2) and [(Dtoq)(2)Cu][Ph(4)P](2) orthoquinone derivatives of V and VI have been obtained by oxidation, and their molecular structures have been determined. The dimeric {[FeS(2)C(6)H(2)(OH)(2)](2)}(2-) complex, (VII) also crystallizes in chains where all OH groups participate in extensive H-bonding. The structure of the dianion VII contains S-coordinated Fe(III) ions in a square pyramidal coordination. In VII, two low spin Fe(III) (S = 1/2) sites are weakly coupled antiferromagnetically with a mu(eff) of 2.81BM at 270 K and 0.91 BM at 10 K.
authors.affiliation: Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA. dcouc@umich.edu
authors.forename: Dimitri
authors.initials: D
authors.lastname: Coucouvanis
authors.forename: Alok R
authors.initials: AR
authors.lastname: Paital
authors.forename: Qinwei
authors.initials: Q
authors.lastname: Zhang
authors.forename: Nicolai
authors.initials: N
authors.lastname: Lehnert
authors.forename: Reinhart
authors.initials: R
authors.lastname: Ahlrichs
authors.forename: Karin
authors.initials: K
authors.lastname: Fink
authors.forename: Dieter
authors.initials: D
authors.lastname: Fenske
authors.forename: Annie K
authors.initials: AK
authors.lastname: Powell
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
mesh_terms: D002396:Catechols / Q000138:chemical synthesis* / Q000737:chemistry; D004581:Electronics; D008024:Ligands; D008280:Magnetics; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D010084:Oxidation-Reduction; D011809:Quinones / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C545236:4,5-dimercaptocatechol; D002396:Catechols; D008024:Ligands; D009942:Organometallic Compounds; D011809:Quinones; D013438:Sulfhydryl Compounds