Electrochemical and photophysical properties of new triazole-bridged heterobimetallic ruthenium-rhodium and ruthenium-iridium complexes

Journal Article · Wed Aug 19 00:00:00 EDT 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00043a008· OSTI ID:6999266

Diemen, J.H. van; Hage, R; Haasnoot, J G; Lempers, H E.B.; Reedijk, J ^[1]; Vos, J G ^[2]; Cola, L de; Barigelletti, F; Balzani, V ^[3]

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1. Leiden Univ. (Netherlands)
2. Dublin City Univ. (Ireland)
3. Ist. FRAE-CNR, Bologna (Italy)

The synthesis, characterization, and the electrochemical and photophysical properties of ((bpy){sub 2}Ru{sup II}(bpt)Rh{sup III}(ppy){sub 2}){sup 2+}, ((bpy){sub 2}Ru{sup II}(bpt)Ir{sup III}(ppy){sub 2}){sup 2+}, ((Rh{sup III}(ppy){sub 2}){sub 2}(bpt)){sup +}, and ((Ir{sup III}(ppy){sub 2}){sub 2}(bpt)){sup +} are reported (Hppy = 2-phenylpyridine; bpy = 2,2{prime}-bipyridine, Hbpt = 3,5-bis(pyridin-2-yl)-1,2,4-triazole). The Ru(bpy){sub 2} moiety is bound via N1 of the triazole ring, while the M(ppy){sub 2} center (M = Rh or Ir) is coordinated via the N4 of the triazole ring. The electrochemical measurements show that in the mixed-metal complexes the first oxidized metal is Ru and the first reduced ligand is bpy. The homobimetallic Ir and Rh complexes exhibit a bpt{sup {minus}}-based reduction. The absorption spectra of the mixed-metal complexes exhibit both Ru {yields} bpy and M {yields} ppy{sup {minus}} transitions. The energies of these transitions are different from those of their homobimetallic analogs. The emission observed for ((Rh(ppy){sub 2}){sub 2}-(bpt)){sup +} at 77 K corresponds to a ligand-centered excited state, while for the analogous iridium complex a charge-transfer emission, which involves the bpt{sup {minus}} ligand, is observed. In the mixed-metal complexes efficient energy transfer occurs from higher energy excited states centered on the M(ppy){sub 2} component to the lowest energy excited state, which is a metal-to-ligand charge transfer level localized on the Ru(bpy){sub 2} component.

• OSTI ID: 6999266
• Journal Information: Inorganic Chemistry; (United States), Vol. 31:17; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IRIDIUM COMPLEXES
OXIDATION
REDUCTION
SPECTROSCOPY
RHODIUM COMPLEXES
RUTHENIUM COMPLEXES
ABSORPTION SPECTROSCOPY
AZOLES
BIPYRIDINES
CHEMICAL PREPARATION
EMISSION SPECTROSCOPY
ENERGY TRANSFER
EXCITED STATES
EXPERIMENTAL DATA
AZINES
CHEMICAL REACTIONS
COMPLEXES
DATA
ENERGY LEVELS
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties