title: Molybdenum- and tungsten(II) monometallic 3-(2-pyridyl)pyrazole and bimetallic 3-(2-pyridyl)pyrazolate complexes.
abstract: Molybdenum and tungsten complexes containing the pypzH (3-(2-pyridyl)pyrazole) ligand as a chelating bidentate are prepared: [Mo(CO)(4)(pypzH)], cis-[MoBr(η(3)-allyl)(CO)(2)(pypzH)], cis-[MoCl(η(3)-methallyl)(CO)(2)(pypzH)], [MI(2)(CO)(3)(pypzH)] (M = Mo, W) from [Mo(CO)(4)(NBD)] or the adequate bis(acetonitrile) complexes. The deprotonation of the molybdenum allyl or methallyl complexes affords the bimetallic complexes [cis-{Mo(η(3)-allyl)(CO)(2)(μ(2)-pypz)}](2) or [cis-{Mo(η(3)-methallyl)(CO)(2)(μ(2)-pypz)}](2) (μ(2)-pypz = μ(2)-3-(2-pyridyl-κ(1)N)pyrazolate-2κ(1)N). The allyl complex was subjected to an electrochemical study, which shows a marked connection between both metallic centres through the bridging pyridylpyrazolates.
authors.affiliation: IU CINQUIMA/Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Arroyo
authors.forename: Daniel
authors.initials: D
authors.lastname: Miguel
authors.forename: Fernando
authors.initials: F
authors.lastname: Villafañe
authors.forename: Elisabete C B
authors.initials: EC
authors.lastname: Alegria
authors.forename: Armando J L
authors.initials: AJ
authors.lastname: Pombeiro