MONONUCLEAR AND BINUCLEAR 3,2-ALPHA-2',3'-C-3'',2'''-H-2''',3'''-J]PHENAZINE (TPPHZ) RUTHENIUM AND OSMIUM COMPLEXES

The monometallic complexes [(bpy)(2)Ru(tpphz)](2+) (4) and [(bpy)(2)Os (tpphz)](2+) (5), where tpphz is the poorly soluble fully aromatic tet rapyrido[3,2-a:2',3'-c:3 '',2 ''-h:2''',3'''-j]phenazine, have been ob tained by reaction of 5,6-diamino-1,10-phenanthroline with [(bpy)(2)M( phendione)](2+) (M = Ru-II or Os-II). Reaction of 4 and 5 with metalli c precursors yielded the home- and heterobimetallic complexes [(bpy)(2 )Ru(tpphz)Ru(NH3)(4)](4+) (6), [(bpy)(2)Ru(tpphz)Ru(bpy)(2)](4+) (7), [(bpy)(2)Os(tpphz)Os(bpy)(2)](4+) (8), and [(bpy)(2)Ru(tpphz)Os(bpy)(2 )](4+) (9). The mononuclear 4 and 5 aggregate in solution, probably by pi-pi stacking of the tpphz part as shown from proton NMR. The comple xes show one reversible metal-centered oxidation and several reversibl e (except 6) reductions which add one electron on the tpphz ligand, on e electron on one bpy of each metallic end, a second electron on one b py of each metallic end, and then a second electron on the tpphz ligan d. The complexes (except 8) are luminescent in acetonitrile. Quenching of the luminescence by water has been attributed to proton quenching at the phenazine nitrogen atoms.