Reductive quenching of the excited states of ruthenium(II) complexes containing 2,2[prime]-bipyridine, 2,2[prime]-bipyrazine, and 2,2[prime]-bipyrimidine ligands

Journal Article · Thu Nov 10 04:00:00 EST 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100096a015· OSTI ID:7079590

Sun, H; Hoffman, M Z ^[1]

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1. Boston Univ., MA (United States)

The reductive quenching of the luminescent excited states of Ru(II) complexes of the general formula Ru-(bpy)[sub 3-m-z](bpm)[sub m](bpz)[sub z][sup 2+] (bpy = 2,2[prime]-bipyridine, bpm = 2,2[prime]-bipyrimidine, bpz = 2,2[prime]-bipyrazine, m and z = 0, 1,2,3 and m + z [le] 3) by aromatic amines and methoxybenzenes as nonsacrificial electron donors and by C[sub 2]O[sub 4][sup 2[minus]], EDTA, and TEOA as sacrificial donors in aqueous, acetonitrile, and propylene carbonate solution was examined by continuous and pulsed laser flash photolysis techniques. From k[sup q], a value of E[sup o] for the irreversible oxidation of TEOA ([minus]0.84 [+-] 0.12 V vs NHE) in acetonitrile was obtained. Values of the cage escape yield of redox products ([eta][sub cc]) showed weak or no dependencies on the driving forces of back electron transfer within the geminate redox pair in the solvent cage ([Delta]G[sub bt][degree]), suggesting that the simple model of competition between cage escape and back electron transfer may be inadequate to describe the results. A modification of the simple model, in which is introduced a kinetically important reorientation of the geminate redox pair, is proposed. 46 refs., 5 figs., 5 tabs.

• OSTI ID: 7079590
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:45; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
664100 -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
AZINES
BIPYRIDINES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
DECOMPOSITION
ELECTRON TRANSFER
ENERGY LEVELS
EXCITED STATES
HETEROCYCLIC COMPOUNDS
KINETICS
LIGANDS
LUMINESCENCE
MATHEMATICAL MODELS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PYRAZINES
PYRIDINES
PYRIMIDINES
QUENCHING
REACTION KINETICS
REDUCTION
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES