Reactivity of Germylene toward Phosphorus-Containing Compounds: Nucleophilic Addition and Tautomerism.

A series of phosphorus-substituted germanium(II) complexes, L(1)GeR [L(1) = CH{(CMe)(2,6-(i)Pr2C6H3N)}2; 2, R = PPh2; 4, R = OPPh2; 5a, R = OP(O)Ph2; 5b, R = OP(O) (O(n)Bu)2; 6a, R = OP(S)Ph2; 6b, R = OP(S)(OEt)2], were synthesized through the direct activation of various organic phosphorus compounds by N-heterocyclic ylide-like germylene 1. These compounds were characterized by IR and NMR spectroscopy, and 4, 5a, 6a, and 6b were further investigated by X-ray crystallography. Interestingly, the reaction of 1 with Ph2P(O)H produced the tricoordinated phosphorus(III) species L(1)GeOPPh2 (4) rather than the expected isomeric product L(1)GeP(O)Ph2. The reaction of 1 with dialkylthiophosphoric acid and diphenylthiophosphinic acid resulted in the products 6a and 6b containing the P═S double bond rather than the P═O double bond.