π-π Interactions in diimine Pt(II) complexes with thiacrown ligands:: The crystal structure of (1,4,7-trithiacyclononane)(3,4,7,8-tetramethyl-1, 10-phenanthroline)platinum(II) hexafluorophosphate

We wish to report the crystal structure for the heteroleptic platinum(II) complex with the crown thioether 1,4,7-trithiacyclononane (9S3) and the diimine ligand 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen), [Pt(9S3)(tmphen)](PF6)(2) (1). The Pt(II) center is surrounded by a cis-S2N2 ligand environment formed by the bidentate diimine and two of the three sulfur atoms from the 9S3 ligand. These two sulfurs are positioned 2.2665(10) and 2.2612(11) angstrom from the Pt(II), but the third sulfur shows a long distance interaction at 2.8849(13) angstrom to form an elongated square pyramidal structure. An examination of the structure reveals pi-pi-intermolecular stacking of the phen groups with alternating distances of 3.53 and 3.62 angstrom between the planes of the phen ligands. A detailed survey of 12 other divalent Pt(II) and Pd(II) diimine complexes of 9S3 reveals three different stacking motifs involving pi-pi interactions in the solid state. Crystal Data for (1): P-1, a = 10.868(2) angstrom, b = 11.292(2) angstrom, c = 11.513(2) angstrom, alpha = 93.76(3)degrees, beta = 90.82(3)degrees, gamma = 92.28(3)degrees, V = 1408.5(5) angstrom(3), Z = 2.