The phosphorus analogues of diazomethane and isomeric diazirine

Diazo compounds and isomeric diazirines have been used as powerful reagents in synthetic chemistry since the first discovery of the parent molecules, diazomethane (CH2 = N = N) and isomeric 3H-diazirine (cyc-CH2N2) in 1890s and 1960s, respectively. In contrast, little is known about their phosphorus analogues. Here, we report on the preparation of methyleneaminophosphinidene (CH2 = N = P) in the gas phase through thermal decomposition of dichlorophosphino(trimethylsilyl)methylamine via the intermediacy of an iminochlorophosphane (MeNPCl). The photochemistry of CH2NP isolated in an Ar-matrix at 10 K reveals predominant wavelength-dependent interconversion with 3H-azaphosphirine (cyc-CH2NP), along with further isomerization to isocyanophosphine (H2PNC) and fragmentation to HCN and PH. By direct photolysis of MeNPCl in an Ar-matrix, the hydrogen-bonded π complex between CH2NP and HCl forms, and it can also undergo reversible photoisomerization with the HCl-complex of cyc-CH2NP. The preparation of CH2NP and cyc-CH2NP significantly advances our fundamental knowledge of organophosphorus chemistry. Diazo compounds and isomeric diazirines have been used as powerful reagents in synthetic chemistry since the first discovery of the parent molecules diazomethane and isomeric 3H-diazirine, but little is known about their phosphorus analogues. Here, the authors report the preparation and characterization of methyleneaminophosphinidene and 3H-azaphosphirine.