title: Color tuning of a nickel complex with a novel N2S2 pyridine-containing macrocyclic ligand.
abstract: The novel pyridine-containing 14-membered macrocycle 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L), which contains an N2S2 donor set, was synthesized, and its protonation behavior was studied by absorption titration with CH3SO3H. The reaction of L with Pd(II) was studied spectroscopically, and the square-planar complex [Pd(L)](BF4) was isolated and characterized. The reactions between L and NiX2 x 6 H2O (X = BF4, ClO4) in ethanol or acetonitrile afforded the octahedral complexes [Ni(CH3CN)(H2O)(L)](X)2 and [Ni(H2O)2(L)](X)2, respectively. The square-planar complexes [Ni(L)](X)2 were obtained by heating these octahedral complexes. Spectrophotometric titrations of [Ni(L)](BF4)2 were performed with neutral and negatively charged ligands. The color of nitromethane solutions of this square-planar complex turns from red to cyan, purple, blue, yellow-green, and pink following addition of halides, acetonitrile, water, pyridine, and 2,2'-bipyridine, respectively. X-ray structural analyses were carried out on the {[Ni(ClO4)(H2O)(L)][Ni(H2O)2(L)]}(ClO4)3, [Ni(CH3CN)(H2O)(L)](ClO4)2, [{Ni(L)}2(mu-Cl)2](ClO4)2, and [{Ni(L)}2(mu-Br)2]Br2 x 2 CH3NO2 complexes.
authors.affiliation: Departament de Química, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Abel
authors.initials: A
authors.lastname: Tamayo
authors.forename: Jaume
authors.initials: J
authors.lastname: Casabó
authors.forename: Lluis
authors.initials: L
authors.lastname: Escriche
authors.forename: Carlos
authors.initials: C
authors.lastname: Lodeiro
authors.forename: Berta
authors.initials: B
authors.lastname: Covelo
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Brondino
authors.forename: Raikko
authors.initials: R
authors.lastname: Kivekäs
authors.forename: Reijo
authors.initials: R
authors.lastname: Sillampää
mesh_terms: D003116:Color; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006574:Heterocyclic Compounds, 2-Ring / Q000737:chemistry*; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D017672:Nitrogen Compounds / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry*
chemical_list: C516277:3,11-dithia-7,17-diazabicyclo(11.3.1)heptadeca-1(17),13,15-triene; D006574:Heterocyclic Compounds, 2-Ring; D008024:Ligands; D047028:Macrocyclic Compounds; D017672:Nitrogen Compounds; D009942:Organometallic Compounds; D011725:Pyridines; D013457:Sulfur Compounds; D009532:Nickel