Synthesis and reactions of molybdenum triamidoamine complexes containing hexaisopropylterphenyl substituents.
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.
Yandulov
Dmitry V
DV
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Schrock
Richard R
RR
Rheingold
Arnold L
AL
Ceccarelli
Christopher
C
Davis
William M
WM
D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D018360:Crystallography, X-Ray; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D013055:Spectrophotometry, Infrared
D008024:Ligands; D009942:Organometallic Compounds; D008982:Molybdenum