Preparation and characterisation of [Pt{N(SePPh₂)₂-Se,Se′}(PR₃)₂]Cl (R = alkyl or aryl); crystal structure of [Pd{Ph₂PNP(Se)Ph₂-P,Se}{N(SePPh₂)₂-Se,Se′}]·0.5EtOH·0.3CH₂Cl₂

Abstract

Reaction of NH(PPh2)2 with selenium gives Ph2P(Se)NHP(Se)Ph2 which may be deprotonated with KOBut to give K[Ph2P(Se)NP(Se)Ph2]. This can be treated with appropriate Group VIII metal complexes to give [Rh{N(SePPh2)2}(cod)](cod = cycloocta-1,5-diene), a series of complexes of formula [Pt{N(SePPh2)2-Se,Se′}(PR3)2]Cl (PR3= PMe3, PMe2Ph, PEt3, PPh3, 1//2NH(PPh2)2 or 1//2Ph2PCH2CH2PPh2) and [MCl{N(SePPh2)2-Se,Se′}(PMe2Ph)](M = Pt or Pd). The new compounds have been characterised by 31P and 195Pt NMR and IR spectroscopy, FAB+ mass spectrometry and microanalyses. Furthermore, a small quantity of a mixed-ligand complex [Pd{Ph2PNP(Se)Ph2-P,Se}{N(SePPh2)2-Se,Se′}]·0.5EtOH·0.3CH2Cl2 has been characterised by X-ray crystallography and 31P NMR spectroscopy. Its structure reveals an approximately planar five-membered PdSeP2N ring and a puckered six-membered PdSe2P2N ring. In the crystal the molecules pack with channels which contain the disordered CH2Cl2 molecules running down the a direction.