Investigations of the Coordination Chemistry of Molybdenum with Facultative Tetradentate Ligands Possessing N2S2 Donor Sets. 2. Preparation, Chemical Characterization, and Electrochemical Study of the Molybdenum(IV)-, Molybdenum(V)-, and Molybdenum(VI)-Oxo Complexes

C. Pickett, S. Kumar, P. A. Vella, Jon Zubieta

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The chemistry of the tetradentate N2S2 donor ligands N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)ethylenediamine (LH2) and N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)-1,3-propanediamine (L′H2) with molybdenum in the VI, V, and IV oxidation states is described. In methanol solution Mo(VI)-oxo reagents combine with LH2 and L′H2 to give [MoO2L] and [MoO2L′]. Reduction of these complexes with HSPh in methanol yields [Mo2O3L2] and [H2Mo2O4L′2]. The more common monooxo-bridged Mo(V) dimer [Mo2O3L′2] may be prepared by the reaction of [MoO2L′] with PMe2Ph in dry THF. The Mo(IV) species [MoOL] and [MoOL′] are obtained by treatment of the Mo(VI) species with excess PMe2Ph in THF solution. The sulfido-bridged dimers [Mo2S4L′2]2− and [MoO2S2L′2]2− have also been prepared. The infrared, electronic, and proton magnetic resonance spectra of these complexes are noted. The electrochemical properties of the complexes are discussed in detail. The significant differences in the redox characteristics of [MoO2L] and [MoO2L′] are reflected in the contrasting reactivity patterns with substituted hydrazines. Whereas [MoO2L] reacts with H2NNR2 and H2NNHR species to give the common monosubstituted derivatives [MoO(N2R2)L] and the disubstituted diazene complexes [Mo(N2R)2L], [MoO2L′] reacts only with benzoylhydrazides (C6H5CONHNH2) to yield the potentially seven-coordinate species [MoO(C6H5CONNH)L′].

Original languageEnglish (US)
Pages (from-to)908-916
Number of pages9
JournalInorganic Chemistry
Issue number3
StatePublished - Jan 1 1982


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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