Intramolar electron transfer in the reductive chromophore-quencher complex ((bpy)Re(CO)/sub 3/(py-PTZ))/sup +/

Journal Article · Wed Apr 08 00:00:00 EDT 1987 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00254a030· OSTI ID:6450571

Chen, P; Westmoreland, T D; Danielson, E; Schanze, K S; Anthon, D; Neveux, Jr, P E; Meyer, T J

Three metal complexes containing the reductive quencher ligand py-PTZ, ((bpy)Re(CO)/sub 3/(py-PTZ))/sup +/ and ((bpy)/sub 2/Ru/sup II/L(py-PTZ))/sup n+/ (where L = Cl/sup -/ (n = 1), PTZ = phenothiazine and acetonitrile ( n = 2)), were prepared and their redox and spectral properties investigated. The chromophore-quencher complex have essentially the same photophysical properties as their corresponding pyridine analogues at 77K in a 4:1 (v/v)) ethanol/methanol glass, but their properties are profoundly different in fluid solution. For the Re complex in fluid solution excitation of the Re..-->.. ..pi..*(bpy) metal to ligand charge-transfer (MLCT) chromophore at 355 nm is followed by rapid (<10 ns) appearance of transient absorption (TA) features at 350 and 500 nm consistent with formation of the charge-separated state ((bpy/sup.-/)Re(CO)/sub 3/(py-PTZ/sup.+))/sup +*/. Picosecond TA experiments monitored at 500 nm show that the PTZ/sup .+/ site grows in within approx.200 ps in polar organic solvents following laser excitation at 355 nm. The transient behavior observed leads to the conclusion that initial excitation of the MLCT chromophore is followed by rapid intramolecular electron-transfer quenching with k/sub q/(RT) = 4.8 x 10/sup 9/ s /sup -1/ in acetonitrile to give the charge-separated excited state ((bpy/sup .-)Re(CO)/sub 3/(py-PTZ/sup.+))/sup +/, which, in turn, decays to the ground state with k/sub 2/ = 4.0 x 10/sup 7/ s/sup -1/. 36 references, 11 figures, 2 tables.

• Research Organization: Univ. of North Carolina, Chapel Hill
• OSTI ID: 6450571
• Journal Information: Inorg. Chem.; (United States), Vol. 26:7
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BIPYRIDINES
ABSORPTION SPECTRA
EMISSION SPECTRA
LUMINESCENCE
REDOX REACTIONS
CARBONYLS
ORGANOMETALLIC COMPOUNDS
PHENOTHIAZINES
RHENIUM COMPLEXES
EXPERIMENTAL DATA
AZINES
CHEMICAL REACTIONS
COMPLEXES
DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PYRIDINES
SPECTRA
TRANSITION ELEMENT COMPLEXES
400201* - Chemical &amp; Physicochemical Properties