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 KOBu^t 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.