Luminescence quenching of dicyanobis(2,2'-bipyridine)ruthenium(II) and dicyanobis(1,10-phenanthroline)ruthenium(II) by transition metal complexes

Abstract

Publication costs assisted by the Petroleum Research FundLuminescence quenching of Ru(b~y),(cN)~ and R~( p h e n )~( C N )~ (bpy = 2,2'-bipyridine and phen = 1,lOphenanthroline) by 19 transition metal complexes is reported. The neutral cyano complexes have properties which permit them to supplement the widely used [Ru(bpy)3I2+ and [R~(phen)~]'+ sensitizers. In addition to their intense, long-lived fluid solution emissions, the cyano complexes are free of ion-pairing problems and the large charge dependence of quenching rates with the tris complexes. The excited state energies of the cyano species can also be tuned significantly by solvent variation. Quenching is predominantly by diffusion. For Co2+, Ni2+, and Cu2+, however, associational quenching by formation of a cyanide bridged species is important. Decay times, excited state energies, Stern-Volmer constants, bimolecular quenching constants, and association constants are reported. Quenching appears to be by energy and electron transfer.

Photodriven heterogeneous charge transfer with transition-metal compounds anchored to TiO2semiconductor surfaces

“…1 Â 10 6 M À1 s À1 . 354,355 Interestingly, excited-state quenching of [Ru III (bpy) 2 (dcb À )] 2+ * anchored to SiO 2 appears to be somewhat more efficient, i.e. 1 Â 10 8 M À1 s À1 .…”

A new efficient photosensitizer for nanocrystalline solar cells: synthesis and characterization of cis-bis(4,7-dicarboxy-1,10-phenanthroline)dithiocyanato ruthenium(II)

“…[5][6][7] The chemistry of 1,10-phenanthroline complexes of ruthenium is often very similar to that of corresponding 2,2Јbipyridyl complexes. 8, 9 Phenanthroline, however, is structurally more rigid and symmetrical; thus we could expect different optical properties in its complexes. Recently, we reported that a tetrabutylammonium salt of cis-bis (1,10- ] shows a remarkable photosensitization when applied to TiO 2 based solar cells.…”

A potential and ion switched molecular photonic logic gate

“…Luminescence quenching by Cu 2+ ions has been previously reported in solution phase studies of the Ru(bpy) 2 (CN) 2 complex. 17 Here, formation of [Ru(bpy) 2 (CN)(CNCu)] 2+ and [Ru(bpy) 2 (CNCu) 2 ] 4+ species results in static quenching of complex luminescence. Dynamic quenching, i.e., luminescence quenching by unbound metal cations diffusing from solution, is also a significant additional pathway.…”

“…Dynamic quenching, i.e., luminescence quenching by unbound metal cations diffusing from solution, is also a significant additional pathway. 17 These switching functions were combined to demonstrate a twoinput molecular photonic logic gate, using the MLCT based luminescence of the complex as the output signal, and the potential applied to the semiconductor substrate, in the presence or absence of Cu 2+ ions, as the input signals. Complex I was synthesized according to previously reported procedures; see Supporting Information.…”