Synthetic studies for the preparation of phosphorus carbonyl rhenacycles with the selenoimidodiphosphinate ligand [N(SePPh2)2]

The synthesis of the rhenacycles [Re(CO)3(PR3){Ph2P(Se)NP(Se)Ph2-κ2Se}], PR3 = PPh3 (1), PMePh2 (2), and PMe2Ph (3) by a straightforward high yield procedure is described. Attempts at the preparation of the spiro [Re(CO)2(Ph2PCH2CH2PPh2-κ2P){Ph2P(Se)NP(Se)Ph2-κ2Se}] resulted in the formation of complexes [Re2(CO)6{Ph2P(Se)NP(Se)Ph2-κ2Se}2(μ-Ph2PCH2CH2PPh2)] (4) and [Re(CO)3(Ph2PCH2CH2PPh2-κ2P){Ph2P(Se)NP(Se)Ph2-κSe}] (5). All new inorganic rhenacycles 1–5 were characterized in solution and in solid state. The X-ray diffraction analysis of [Re(CO)3PPh3{Ph2P(Se)NP(Se)Ph2-κ2Se}] showed that its MnSePNPSe ring conformation is sensitive to temperature.