Synthesis and reactions of molybdenum triamidoamine complexes containing hexaisopropylterphenyl substituents

Inorg Chem. 2003 Feb 10;42(3):796-813. doi: 10.1021/ic020505l.

Abstract

We have synthesized a triamidoamine ligand ([(RNCH(2)CH(2))(3)N](3)(-)) in which R is 3,5-(2,4,6-i-Pr(3)C(6)H(2))(2)C(6)H(3) (hexaisopropylterphenyl or HIPT). The reaction between MoCl(4)(THF)(2) and H(3)[HIPTN(3)N] in THF followed by 3.1 equiv of LiN(SiMe(3))(2) led to formation of orange [HIPTN(3)N]MoCl. Reduction of MoCl (Mo = [HIPTN(3)N]Mo) with magnesium in THF under dinitrogen led to formation of salts that contain the ((Mo(N(2)))(-) ion. The (Mo(N(2)))(-) ion can be oxidized by zinc chloride to give Mo(N(2)) or protonated to give MoN=NH. The latter was found to decompose to yield MoH. Other relevant compounds that have been prepared include (Mo=N-NH(2))(+) (by protonation of MoN=NH), M=1;N, (Mo=NH)(+) (by protonation of M=N), and (Mo(NH(3)))(+) (by treating MoCl with ammonia). (The anion is usually (B(3,5-(CF(3))(2)C(6)H(3))(4))(-) = (BAr'(4))(-).) X-ray studies were carried out on (Mg(DME)(3))(0.5)[Mo(N(2))], MoN=NMgBr(THF)(3), Mo(N(2)), M=N, and (Mo(NH(3)))(BAr'(4)). These studies suggest that the HIPT substituent on the triamidoamine ligand creates a cavity that stabilizes a variety of complexes that might be encountered in a hypothetical Chatt-like dinitrogen reduction scheme, perhaps largely by protecting against bimolecular decomposition reactions.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Catalysis
  • Chemistry, Organic / methods
  • Crystallography, X-Ray
  • Ligands
  • Magnetic Resonance Spectroscopy
  • Molecular Conformation
  • Molecular Structure
  • Molybdenum / chemistry*
  • Organometallic Compounds / chemical synthesis*
  • Organometallic Compounds / chemistry*
  • Oxidation-Reduction
  • Spectrophotometry, Infrared

Substances

  • Ligands
  • Organometallic Compounds
  • Molybdenum