Asymmetric ruthenium(II) and osmium(II) complexes with new bidentate polyquinoline ligands. Synthesis and NMR characterization

Abstract

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,1H-NMR and FAB-MS techniques. The new ligands are: L1 = 4-p-methoxyphenyl-6-bromo-2-(2'-pyridyl)quinoline (mphbr-pq) and L2 = 4-p-hydroxyphenyl-6-bromo-2-(2'-pyridyl)-quinoline (hphbr-pq). The complexes studied are: [Ru(bpy)2L1](PF6)2 (C1), [Ru(bpy)2L2](PF6)2 (C2), [Os(bpy)2L1](PF6)2 (C3), [Os(bpy)2L2](PF6)2 (C4) (bpy = 2,2'-bipyridine), [Ru(dmbpy)2L 1](PF6)2 (C5), [Ru(dmbpy) 2L2](PF6)2 (C6), [Os(dmbpy)2L1](PF6)2 (C 7), and [Os(dmbpy)2L2](PF6) 2 (C8) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine). Moreover, new functionalized complexes C9-C12 were obtained by the basecatalyzed direct alkylation of C2, C4, C6, and C8 with 6-bromo-1-hexene. The complete assignment of the 1H-NMR spectra for the two new ligands (L1 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 JH,H values have been determined for the majority of the resonances. © 2010 by the authors.