Preparation, structure and coordination properties of 3,3-bis(diisopropylamino)-3-thioxo-1-(2,4,6-tri-tert-butylphenyl)1,3-diphosphapropene

(Z)-1-Chloro-2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyllithium was allowed to react with bis(diisopropylamino)-phosphenium triflate to afford the corresponding 1,3-diphosphapropene which was converted to 3-thioxo-1,3-diphosphapropene [(Z)-Mes*P=C(Cl)-P(=S)((NPr2)-Pr-i)(2)]. The coordination properties of 3-thioxo-1,3-diphosphapropene were investigated with carbonyltungsten(0) and dichloroplatinum(II) reagents, and the molecular structure of the chelate dichloroplatinum(II) complex was unambiguously determined by X-ray crystallography together with the free ligand. The dichloroplatinum(II) complex underwent intramolecular cyclisation involving C-H activation to give a 5,7-di-tert-butyl-3,3-dimethyl-1-(phosphinomethyl)-1-phosphaindane derivative as well.