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One saturated ring spirophosphazene 2 and cyclic phosphazenes 3 were prepared by reaction of triazaphospholes 1 with amines and diamines and iodine or enamine.

The first step of hydrolysis of compounds 1 , 2 and 4 involves the protonation of the PN nitrogen atom. 3 does not react with water in the absence of a catalyst. Protonation of compounds 1 – 3 by a strong acid such as CF3SO3H is studied by 15N and 31P nmr spectroscopy. In all cases the PN nitrogen appears to be the strongest basic site.

So far organophosphorus chemists have been interested in synthesizing low coordinated phosphorus compounds and in studying them in solution at temperatures rarely above 300 °C. As a matter of fact there are few reports on the behaviour of dicoordinated phosphorus molecules at temperatures above 500 °C under low pressure. Another interesting point is that such a study would allow to assess the correla- tion between mass spectral processes and thermal ones.

Addition of diazadienes 5 to dicoordinated phosphorus derivatives such as triazaphospholes 1 or diazaphospholes 3 leads to new tetracoordinated phosphorus spirocompounds 2 or 4. The tricoordinated phosphorus species 7 and 9 exist in a monomer tetramer PIII equilibrium but only the monomeric PII form reacts with diazadienes 5 leading to the spirocompounds 8 and 10. The monomers of 7 and 9 stabilized by complexation react with 5 to afford spirocompounds analogous to 2 and 4. In all these reactions the dicoordinated phosphorus atom is a good electrophile.

Triazaphospholes react with 1,2-diketones to give spirocyclic phosphorus compounds by a 1.1 addition at phosphorus atom; with o-quinones one obtains spirobicyclic hexacoordinated phosphorus compounds. The reaction of 1,2-diketones with λ 3 -phosphazene oligomers appears different, to some extent, and can be used as a test for the existence of a monomer-oligomer equilibrium.