Synthetic and structural studies of heteroleptic platinum(ii) complexes containing crown trithioether and diphosphine ligandsHeteroleptic platinum(ii) complexes with crown thioether and phosphine ligands. Part IV.1

Abstract

We wish to report the syntheses and spectroscopic properties of seven new Pt(II) heteroleptic complexes containing a series of diphosphine [P2 = Ph2PCH2CH2PPh2 (dppe), Ph2P(CH2)3PPh2 (dppp), Ph2P(CH2)4PPh2 (dppb), Ph2P(CH2)5PPh2 (dpppe), 1,2-Ph2PC6H4PPh2 (dppbe), and 1,2-Ph2C2H2PPh2 (dppv)] ligands and the crown trithioethers [9]aneS3 (1,4,7-trithiacyclononane) or [10]aneS3 (1,4,7-trithiacyclodecane). All seven reported complexes have the general formula [Pt([n]aneS3)(P2)](PF6)2 and form similar structures in which the Pt(II) center is surrounded by a cis arrangement of the two P donors from the diphosphine chelate and two sulfur atoms from the trithioether ligand. The third sulfur atom forms a longer interaction with the platinum resulting in an elongated square pyramidal structure with Pt–S axial distances ranging from 2.6505(9) to 2.8766(17) A. The 195Pt NMR chemical shifts for the complexes show values in the range of −4400 to −4700 ppm, consistent with a cis-PtS2P2 coordination sphere.