The reactivity of trans-diiodoplatinum(II) complexes containing five and six-membered N-heterocycle ligands toward some diphosphine ligands

Abstract

The known complex trans-[Pt2I2(μ-I)2(dmso)2], 1, was reacted with 2 or 4equiv of 1-methylimidazole and 4-methylpyridine as two different N-heterocycle ligands. The symmetrical cleavage of this di-nuclear structure by 2 and 4equiv of 1-methylimidazole led to formation of the complexes trans-[PtI2(1-MeIm)(dmso)], 2, and trans-[PtI2(1-MeIm)2], 4, respectively. In the case of 4-methylpyridine, the reaction of 1 with both 2 and 4equiv of the ligand ended up to the complex trans-[PtI2(4-MePy)(dmso)], 3. Also, the reactivity of the complexes 2 and 4 was investigated toward some common diphosphine ligands. The complexes 5, 6 and 7 with general formula of [PtI2(P^P)] were formed when the complexes 2 and 4 were reacted with dppm, dppe and dppp ligands respectively while the dinuclear complexes 8 and 11 with bridging diphosphine were formed using the linear dppac ligand. The complexes were fully characterized using the multinuclear (1H and 31P{H}) NMR spectroscopy and elemental analysis. The structure of typical complex 2 was further determined by X-ray crystallography. Also, DFT calculations were performed in order to gain the optimized structures and further insight into the nature of the absorption characters of the new complexes.