Complexes with a metal phosphorus triple bond - a novel class of highly reactive compounds

A novel approach to highly reactive phosphido complex intermediates of the type [LnM dropP -->M'(CO)(5)] (M' = Cr, W) is achieved via the Cp* migratio n from a sigma -bound situation at a P atom in a phosphinidene complex [Cp* P{W(CO)(5)}2] to the eta (5)-coordination at the transition metal. Conseque ntly those compounds show a high "side-on" reactivity. Their reaction behav ior with phosphaalkynes, alkynes and nitriles leads to novel metala-phospha heterocycles. Furthermore, the use of the corresponding As analogue [Cp*As{ W(CO)(5)}2] yields via thermolysis reaction the tetranuclear tungsten clust ers, which indicate besides the formation of the triple bond intermediate [ Cp*(CO)(2)W drop As -->W(CO)(5)] the occurrence of a second Cp* eliminated intermediate [As{W(CO)(5)}(2)].