Asymmetric Ruthenium(II) and Osmium(II) Complexes with New Bidentate Polyquinoline Ligands. Synthesis and NMR Characterization

A series of Ru(II) and Os(II) tris-chelate complexes with new bidentate 2-pyridylquinoline ligands have been synthesized and fully characterized by EA, H-1-NMR and FAB-MS techniques. The new ligands are: L-1 = 4-p-methoxyphenyl-6-bromo-2-(2'-pyridyl)quinoline (mphbr-pq) and L-2 = 4-p-hydroxyphenyl-6-bromo-2-(2'-pyridyl)quinoline (hphbr-pq). The complexes studied are: [Ru(bpy)(2)L-1](PF6)(2) (C-1), [Ru(bpy)(2)L-2](PF6)(2) (C-2), [Os(bpy)(2)L-1](PF6)(2) (C-3), [Os(bpy) L-2(2)](PF6)(2) (C-4) (bpy = 2,2'-bipyridine), [Ru(dmbpy)(2)L-1](PF6)(2) (C-5), [Ru(dmbpy)(2)L-2](PF6)(2) (C-6), [Os(dmbpy)(2)L-1](PF6)(2) (C-7), and [Os(dmbpy)(2)L-2](PF6)(2) (C-8) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine). Moreover, new functionalized complexes C-9-C-12 were obtained by the base-catalyzed direct alkylation of C-2, C-4, C-6, and C-8 with 6-bromo-1-hexene. The complete assignment of the H-1-NMR spectra for the two new ligands (L-1 and L-2), and their Ru(II) or Os(II) complexes has been accomplished using a combination of one-and two-dimensional NMR techniques. The J(H,H) values have been determined for the majority of the resonances.