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) Å from the Pt(II), but the third sulfur shows a long distance interaction at 2.8849(13) Å to form an elongated square pyramidal structure. An examination of the structure reveals π–π-intermolecular stacking of the phen groups with alternating distances of 3.53 and 3.62 Å 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 π–π interactions in the solid state. Crystal Data for (1): P-1, a = 10.868(2) Å, b = 11.292(2) Å, c = 11.513(2) Å, α = 93.76(3)°, β = 90.82(3)°, γ = 92.28(3)°, V = 1408.5(5) Å3, Z = 2.