NMR study of mononuclear, binuclear and trinuclear tris(hydroxymethyl)phosphine-platinum(II) complexes with aquo or hydroxo ligands

Abstract

Treatment of [PtX 2{P(CH 2OH) 3} 2] (X=Cl or Br) with AgY (Y=NO 3, BF 4, PF 6 or ClO 4) in water gives three species A, B and C. Addition of HY to this mixture gives A exclusively which is identified as the bis(aquo) cation [Pt(OH 2) 2{P(CH 2OH) 3} 2] 2+. The aquo ligands can be substituted by pyridine, 2,2′-bipyridine or 9,10-phenanthroline to give the corresponding [PtL 2{P(CH 2OH) 3} 2] 2+. Treatment of [Pt(OH 2) 2{P(CH 2OH) 3} 2] 2+ with NEt 3 gives B which is identified as the binuclear species [Pt 2(μ-OH) 2{P(CH 2OH) 3} 4] 2+. After 24 h in acid solution in the presence of Ag +, the third species C is the main product which is trinuclear (as evidenced by 31P and 195Pt NMR spectroscopy) and is assigned the structure [Pt 3(μ-OH) 3{P(CH 2OH) 3} 6] 3+. The products are very soluble in water and have been characterised only by 31P and 195Pt NMR spectroscopy. The chemistry of these P(CH 2OH) 3 complexes is compared with the chemistry of the analogous PMe 3 complexes.