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,(1)H-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)](PF(6))(2) (C(1)), [Ru(bpy)(2)L(2)](PF(6))(2) (C(2)), [Os(bpy)(2)L(1)](PF(6))(2) (C(3)), [Os(bpy)(2)L(2)](PF(6))(2) (C(4)) (bpy = 2,2′-bipyridine), [Ru(dmbpy)(2)L(1)](PF(6))(2) (C(5)), [Ru(dmbpy)(2)L(2)](PF(6))(2) (C(6)), [Os(dmbpy)(2)L(1)](PF(6))(2) (C(7)), and [Os(dmbpy)(2)L(2)](PF(6))(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 (1)H-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.