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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2001-9-4
pubmed:abstractText
We synthesized azobenzene-conjugated bis(terpyridine) Ru(II) and Rh(III) mononuclear and dinuclear complexes and investigated their photochemical properties on excitation of the azo pi-pi band upon 366 nm light irradiation. The Ru mononuclear complex underwent trans-to-cis photoisomerization to reach the photostationary state with only 20% of the cis form, while the Ru dinuclear complex did not isomerize at all photochemically. On the other hand, the mononuclear and dinuclear Rh complexes showed almost complete trans-to-cis photoisomerization behavior. Cis forms of the Rh complexes thermally returned to the trans form at a much slower rate than those of organic azobenzenes, but they did not isomerize photochemically. The reduction potential of the cis forms was 80 mV more negative than that of the trans forms. The photoisomerization quantum yields of the Rh complexes were strongly dependent on the polarity, viscosity, and donor site of the solvents as well as the size of the counterions. We investigated the photoisomerization process of these complexes using femtosecond absorption spectroscopy. For the Rh complexes, we observed S(n) <-- S(2) and S(n) <-- S(1) absorption bands similar to those of organic azobenzenes. For the Ru complexes, we observed very fast bleaching of the MLCT band of the Ru complex, which indicated that the energy transfer pathway to the MLCT was the primary cause of the depressed photoisomerization. The electronic structures, which were estimated from ZINDO molecular orbital calculation, supported the different photochemical reaction behavior between the Ru and Rh complexes.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Sep
pubmed:issn
0020-1669
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4986-95
pubmed:dateRevised
2003-10-31
pubmed:year
2001
pubmed:articleTitle
Synthesis, characterization, and photochemical properties of azobenzene-conjugated Ru(II) and Rh(III) bis(terpyridine) complexes.
pubmed:affiliation
Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
pubmed:publicationType
Journal Article