Synthesis of transition-metal complexes with heterodifunctional ligands derived of NH(PPh2)2. Crystal structure of [(η5-C5Me5)RhCl{η2-P,Se-Ph2PNP(Se)Ph2}]·CH2Cl2

The uncoordinated P atom of the bis(diphenylphosphine)amine (dppa) ligand in complexes [(ring)MCl2(η1-P-PPh2NHPPh2)] (M=Rh, Ir, Ru) reacts with sulphur or selenium to form [(ring)MCl2(η1-P-PPh2NHP(E)Ph2)] (E=S (1–3), Se (4–6)) containing the P-coordinated monosulphide or monoselenide ligands. The selenium derivatives have also been directly prepared from the corresponding [{(ring)MCl2}2] dimer and dppaSe. Chloride abstraction from rhodium and ruthenium complexes gives the neutral compounds [(ring)MCl(η2-P,E-PPh2NP(E)Ph2)] (7–10) whilst the iridium derivatives yield cationic complexes of the general formula [{η5-C5Me5)IrCl(η2-P,E-PPh2NHP(E)Ph2)]+ (11 and 12). The crystal structure of complex [(η5-C5Me5)RhCl{η2-P,Se-PPh2NP(Se)Ph2}] has been established by X-ray crystallography. The rhodium atom exhibits a distorted octahedral coordination with a η5-C5Me5 group occupying the centre of three octahedral sites; a bidentate chelate P,Se-bonded ligand and a chloride atom complete the metal coordination sphere.