title: Synthesis and oxidative reactivity of 2,2'-pyridylpyrrolide complexes of Ni(II).
abstract: Synthesis and characterization of divalent nickel complexed by 2-pyridylpyrrolide bidentate ligands are reported, as possible precursors to complexes with redox active ligands. Varied substituents on the pyrrolide, two CF3 (L(2)), two (t)Bu (L(0)), and one of each type (L(1)) are employed and the resulting Ni(L(n))2 complexes show different Lewis acidity toward CO, H2O, tetrahydrofuran (THF), or MeCN, the L(2) case being the most acidic. Density functional theory calculations show that the frontier orbitals of all three Ni(L(n))2 species are localized at the pyrrolide groups of both ligands and Ni(L(n))2(+) can be detected by mass spectrometry and in cyclic voltammograms (CVs). Following cyclic voltammetry studies, which show electroactivity primarily in the oxidative direction, reactions with pyridine N-oxide or Br2 are reported. The former yield simple bis adducts, Ni(L(2))2(pyNO)2 and the latter effects electrophilic aromatic substitution of the one pyrrolide ring hydrogen for both chelates, leaving it brominated.
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405-7102, United States.
authors.forename: Nikolay P
authors.initials: NP
authors.lastname: Tsvetkov
authors.forename: Chun-Hsing
authors.initials: CH
authors.lastname: Chen
authors.forename: José G
authors.initials: JG
authors.lastname: Andino
authors.forename: Richard L
authors.initials: RL
authors.lastname: Lord
authors.forename: Maren
authors.initials: M
authors.lastname: Pink
authors.forename: René W
authors.initials: RW
authors.lastname: Buell
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Caulton
mesh_terms: D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D011758:Pyrroles / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D009942:Organometallic Compounds; D011758:Pyrroles; D009532:Nickel