CHIRAL CYCLOMETALATED PLATINUM(II) AND PALLADIUM(II) COMPLEXES WITH DERIVATIVES OF THIENYLPYRIDINE AS LIGANDS - HELICAL DISTORTION OF THE SQUARE-PLANAR (SP-4) GEOMETRY

Four cis-bis-cyclometalated complexes of platinum(II) and palladium(II ) have been synthesized with chiral substituted thienylpyridine ligand s. These ligands are -dimethyl-3-(2'-thienyl)-cyclopropa[g]isoquinolin e (th4,5capy) (1), -7,7-dimethyl-2-(2'-thienyl)cyclopropa[h]quinoline (th5,6capy) (2), ro-9,9-dimethyl-2-(2'thienyl)-6,8-methanoquinoline (t h5,6 beta ppy) (3), and (6R,8R)-5,6,7,8-tetrahydro-9,9-dimethyl-(th4,5 ppy) (5). Two complexes have a well-defined chirality at the metal cen ter, due to the sterical interaction of the ligands. These complexes a re Delta-Pt(th5,6capy)(2) (8) and Lambda-Pt(th5,6 beta ppy)(thpy) (9). The crystal structure of 8 shows a strong distortion from the ideal s quare planar geometry. Crystals of Delta-Pt(th5,6capy)(2) (8) are tetr agonal, space group P4(3)2(1)2, a = 13.407(1) Angstrom, b = 13.407(1) Angstrom, c = 14.860(2) Angstrom, alpha = beta = gamma = 90 degrees, a nd Z = 4. Final R = 0.0237 and R-w = 0.0450 for 2353 observed reflecti ons. Compound 8 possesses a crystallographic C-2 symmetry.