In Search of Fulminate Analogues: LnM≡CP=NR.

The "CPNR" ligand may be viewed as being isolobal with fulminate, CNO; however, attempts to prepare a complex of such a ligand resulted instead in a range of novel imino and aminophosphinocarbyne complexes. Sequential treatment of [Mo(≡CBr)(CO)2(Tp*)] (Tp*=hydrotris(dimethylpyrazolyl)borate) with nBuLi and ClP=NMes* (Mes*=C6H2tBu3‐2,4,6) afforded mixtures of the complexes [Mo(≡CPnBuNHMes*)(CO)2(Tp*)] and traces of the bimetallic products [Mo2{μ2‐C2P2O(NHMes)2}(CO)4(Tp*)2] and [Mo2(μ2‐C2PNHMes)(CO)4(Tp*)2]. The reaction of [W(≡CBr)(CO)2(Tp*)] with nBuLi and ClP=NMes* afforded predominantly the mononuclear carbyne [W{≡CP(=NMes*)nBu2})(CO)2(Tp*)] and traces of the binuclear complex [W2(μ‐C2PNHMes)(CO)4(Tp*)2] which is also obtained when tBuLi is used. Although not isolable, the intended complexes [M(≡CPNMes*)(CO)2(Tp*)] could be generated in situ and spectroscopically characterized via the reactions of the stannyl carbynes [M(≡CSnnBu3)(CO)2(Tp*)] and ClP=NMes*. The preceding observations are mechanistically interpreted with reference to a computational interrogation of the model complex [Mo(≡CP=NCH3)(CO)2(Tp*)], the LUMO of which has considerable phosphorus character. [ABSTRACT FROM AUTHOR]