Palladium and platinum complexes of tellurium-containing imidodiphosphinate ligands: nucleophilic attack of Li[(PiPr2)(TePiPr2)N] on coordinated 1,5-cyclooctadiene

Abstract

Homoleptic group 10 complexes of ditellurido PNP (PNP = imidodiphosphinate), heterodichalcogenido PNP and monotellurido PNP ligands, M[(TePⁱPr₂)₂N]₂ (1: M = Pd; 2: M = Pt), M[(EPⁱPr₂)(TePⁱPr₂)N]₂ (3: M = Pd, E = Se; 4: M = Pt, E = Se; 5: M = Pd, E = S; 6: M = Pt, E = S) and M[(PⁱPr₂)(TePⁱPr₂)N]₂ (7: M = Pd; 8: M = Pt), respectively, were prepared by metathesis between alkali-metal derivatives of the appropriate ligand and MCl₂(COD) in THF. Complexes 1–8 were characterised in solution by multinuclear (³¹P, ⁷⁷Se, ¹²⁵Te and ¹⁹⁵Pt) NMR spectroscopy and, in the case of 1, 2, trans-7, cis-7 and trans-8, in the solid state by X-ray crystallography. The square-planar complexes 3–6 are formed as a mixture of cis- and trans-isomers on the basis of NMR data. The cis and trans isomers of 7 were separated by crystallisation from different solvents. In addition to trans-8, the reaction of Li[(PⁱPr₂)(TePⁱPr₂)N] with MCl₂(COD) produced the heteroleptic complex Pt[(PⁱPr₂)(TePⁱPr₂)N][σ:η²-C₈H₁₂(PⁱPr₂NPⁱPr₂Te)] (9) resulting from nucleophilic attack on coordinated 1,5-cyclooctadiene. Complex 9 was identified by multinuclear (¹³C, ³¹P, ¹²⁵Te and ¹⁹⁵Pt) NMR spectroscopy, which revealed a mixture of geometric isomers, and by X-ray crystallography.