Ammonia is released from the metallo-imide trans-[W(NH)(OMe)(Ph2PCH2CH2PPh2)2]+ without degradation of the phosphine ligand assembly by a hydrolysis reaction which gives the oxide trans-[WOCl(Ph2PCH2CH2PPh2)2]+; and this oxide and its Mo analogue are reduced at a mercury cathode in the presence of molecular nitrogen with phenol as a proton source to give trans-[M(N2)2(Ph2PCH2CH2PPh2)2](M = Mo or W); the primary reduction potentials of the Mo and W oxides are substantially positive of those of their isostructural imide counterparts and this suggests a possible role for oxides in biological nitrogen fixation.
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