1346558-16-4Relevant academic research and scientific papers
Small-Molecule Activation within the Group 6 Complexes (η5-C5Me5)[N(iPr)C(Me)N(iPr)]M(CO)(L) for M = Mo, W and L = N2, NCMe, η2-Alkene, SMe2, C3H6O
Farrell, Wesley S.,Yonke, Brendan L.,Reeds, Jonathan P.,Zavalij, Peter Y.,Sita, Lawrence R.
, p. 1132 - 1140 (2016)
A series of midvalent monocyclopentadienyl monoamidinate (CPAM) group 6 complexes of the general formula Cp?[N(iPr)C(Me)N(iPr)]M(CO)(L) (II), where Cp? = η5-C5Me5 and M = Mo, W, have been prepared, and most of them have been structurally characterized. Treatment of the ditungsten "end-on-bridged" dinitrogen complex {Cp?[N(iPr)C(Me)N(iPr)]W}2(μ-η1:η1-N2) (3) with excess NCMe under a CO atmosphere produced the ditungsten bridging diimido complex {Cp?[N(iPr)C(Me)N(iPr)]W}2[μ-η1:η1-NC(Me)=(Me)N] (4). Photolysis of Cp?[N(iPr)C(Me)N(iPr)]M(CO)2, where M = Mo (6), W (7), or treatment of Cp?[N(iPr)C(Me)N(iPr)]Mo(CO)(NCMe) (1a) with excess alkene provided Cp?[N(iPr)C(Me)N(iPr)]M(CO)(L) for M = Mo and L = η2-ethene (8), M = W and L = η2-ethene (9), M = Mo and L = η2-norbornene (10), M = W and L = η2-norbornene (11), M = W and L = η2-cyclopentene (12), M = Mo and L = η2-cyclopentene (13), and M = Mo and L = η2-styrene (14). When isobutene was employed as the alkene, C-H bond activation occurred to produce Cp?[N(iPr)C(Me)N(iPr)]W(H)(η3-C4H7) (15). Photolysis of 7 in the presence of SMe2 provided Cp?[N(iPr)C(Me)N(iPr)]W[κ-C,O-C(O)Me](SMe) (16) through oxidative C-S bond activation of a coordinated SMe2, followed by 1,1-carbonyl migratory insertion into the new W-C bond. Finally, reaction of 1a with propylene oxide (C3H6O) provided the 16-electron complex Cp?[N(iPr)C(Me)N(iPr)]Mo[C(O)CH(Me)CH2O] (19) via similar oxidative C-O bond activation of coordinated C3H6O, followed by 1,1-carbonyl migratory insertion into the Mo-C bond of an intermediate metallaoxetane. Under a CO atmosphere, 19 is converted to the 18-electron complex Cp?[N(iPr)C(Me)N(iPr)]Mo[C(O)CH(Me)CH2O](CO) (20). These results provide additional support for the development of new stoichiometric and catalytic transformations that are mediated by CPAM group 6 metal complexes and that are relevant to the goal of small-molecule fixation.
Metal-Mediated Production of Isocyanates, R3EN=C=O from Dinitrogen, Carbon Dioxide, and R3ECl
Keane, Andrew J.,Farrell, Wesley S.,Yonke, Brendan L.,Zavalij, Peter Y.,Sita, Lawrence R.
supporting information, p. 10220 - 10224 (2015/09/01)
A highly efficient and versatile chemical cycle has been developed for the production of isocyanates through the molecular fixation of N2, CO2 and R3ECl (E=C, Si, and Ge). Key steps include a 'one-pot' photolytic N-N bond cleavage of a Group6 dinuclear dinitrogen complex with insitu trapping by R3ECl to provide a metal terminal imido complex that can engage in simultaneous nitrene-group transfer and oxygen-atom transfer to generate an intermediate metal terminal oxo complex with release of the isocyanate product. Reaction of the oxo complex with additional equivalents of R3ECl regenerates a metal dichloride that is the precursor for dinuclear dinitrogen starting material.
