Catalytic Dinitrogen Reduction to Ammonia at a Triamidoamine–Titanium Complex |
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| Authors: | Dr Laurence R Doyle Dr Ashley J Wooles Lucy C Jenkins Dr Floriana Tuna Prof Eric J L McInnes Prof Stephen T Liddle |
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| Institution: | 1. School of Chemistry, The University of Manchester, Manchester, UK;2. School of Chemistry, The University of Nottingham, Nottingham, UK;3. School of Chemistry and Photon Science Institute, The University of Manchester, Manchester, UK |
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| Abstract: | Catalytic reduction of N2 to NH3 by a Ti complex has been achieved, thus now adding an early d‐block metal to the small group of mid‐ and late‐d‐block metals (Mo, Fe, Ru, Os, Co) that catalytically produce NH3 by N2 reduction and protonolysis under homogeneous, abiological conditions. Reduction of TiIV(TrenTMS)X] (X=Cl, 1A ; I, 1B ; TrenTMS=N(CH2CH2NSiMe3)3) with KC8 affords TiIII(TrenTMS)] ( 2 ). Addition of N2 affords {(TrenTMS)TiIII}2(μ‐η1:η1‐N2)] ( 3 ); further reduction with KC8 gives {(TrenTMS)TiIV}2(μ‐η1:η1:η2:η2‐N2K2)] ( 4 ). Addition of benzo‐15‐crown‐5 ether (B15C5) to 4 affords {(TrenTMS)TiIV}2(μ‐η1:η1‐N2)]K(B15C5)2]2 ( 5 ). Complexes 3 – 5 treated under N2 with KC8 and R3PH]I], (the weakest H+ source yet used in N2 reduction) produce up to 18 equiv of NH3 with only trace N2H4. When only acid is present, N2H4 is the dominant product, suggesting successive protonation produces {(TrenTMS)TiIV}2(μ‐η1:η1‐N2H4)]I]2, and that extruded N2H4 reacts further with R3PH]I]/KC8 to form NH3. |
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| Keywords: | ammonia dinitrogen reduction nitrogen fixation phosphonium salts titanium |
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