Palladium and platinum complexes of tellurium-containing imidodiphosphinate ligands: nucleophilic attack of Li[((PPr2)-Pr-i)((TePPr2)-Pr-i)N] on coordinated 1,5-cyclooctadiene

Homoleptic group 10 complexes of ditellurido PNP (PNP = imidodiphosphinate), heterodichalcogenido PNP and monotellurido PNP ligands, M[((TePPr2)-Pr-i)(2)N](2) (1: M = Pd; 2: M = Pt), M[((EPPr2)-Pr-i)((TePPr2)-Pr-i)N](2) (3: M = Pd, E = Se; 4: M = Pt, E = Se; 5: M = Pd, E = S; 6: M = Pt, E = S) and M[((PPr2)-Pr-i)((TePPr2)-Pr-i)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 (P-31, Se-77, Te-125 and Pt-195) 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[((PPr2)-Pr-i)((TePPr2)-Pr-i)N] with MCl2(COD) produced the heteroleptic complex Pt[((PPr2)-Pr-i)((TePPr2)-Pr-i)N][sigma:eta(2)-C8H12((PPr2NPPr2Te)-Pr-i-Pr-i)] (9) resulting from nucleophilic attack on coordinated 1,5-cyclooctadiene. Complex 9 was identified by multinuclear (C-13, P-31, Te-125 and Pt-195) NMR spectroscopy, which revealed a mixture of geometric isomers, and by X-ray crystallography.