Heteroleptic platinum(II) complexes with crown thioether and phosphine ligands: the crystal structures of [Pt(9S3)(PPh 3)Cl](PF 6)·CH 3NO 2 and [Pt(10S3)(PPh 3)Cl](PF 6)

Abstract

We wish to report the synthesis, spectroscopic properties, and crystal structures of two Pt(II) heteroleptic complexes with triphenylphosphine (PPh 3), chloride, and the crown trithioethers 9S3 (1,4,7-trithiacyclononane) or 10S3 (1,4,7-trithiacyclodecane). Both complexes have the general formula [Pt(L)(PPh 3)Cl](PF 6) (L=9S3 or 10S3) and form similar structures in which the Pt(II) center is surrounded by a cis arrangement of the chloride, the P donor from the phosphine, and two sulfur atoms from the 9S3 ligand. The third sulfur in each structure forms a longer interaction with the platinum resulting in an elongated square pyramidal structure. The 195Pt NMR chemical shifts for both complexes show a value near −4100 ppm, consistent with a cis-PtS 2PCl coordination sphere. The trithioethers in both complexes are fluxional, resulting in relatively simple 13C NMR spectra for them (9S3, one line; 10S3, four lines). Although the fluxional behavior of the 9S3 ligand in platinum group metal complexes is well-documented, our NMR and structural data confirm definite fluxional behavior of the 10S3 ligand for the first time.