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Publication Type
Journal Article
UWI Author(s)
Author, Analytic
Gooden, V.,; Dasgupta, Tara, P.; Gordon, N.; Sadler, Garfield G.
Author Affiliation, Ana.
Chemistry; Faculty of Pure and Applied Sciences
Article Title
Properties and kinetics of dihydroxy- and diaminoanthraquinone ruthenium bipyridyl dimers
Medium Designator
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Connective Phrase
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Journal Title
Inorganica Chimica Acta
Translated Title
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Reprint Status
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Date of Publication
1998
Volume ID
268
Issue ID
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Page(s)
31-36
Language
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Connective Phrase
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Location/URL
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ISSN
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Notes
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Abstract
Ru (bpy)2C12 (bpy:2,2' -bipyridine) reacts with 1,4-diaminoanthraquinone (1,4-DAAQ) to produce a dimeric complex which precipitates from solution in its mixed-valence form. Redox couples show that the rutheniums are easier to oxidize than those in the corresponding 1,4- DHAQ (1,4-dihydroxyanthraquinone) and 1,4-AHAQ (1-amino-4-hydroyanthraquinone) dimers and give a value of 2.8 x 106 for Kcom. Visible absorbtion bands are broad and may be combinations of transitions. The IT band in acetonitrile shows structure with lmax (log ) at 845 nm (3.5), 1493 nm (4.44) and 2028 nm (4.04). Preliminary kinetic studies of the S2O82- oxidation of the 1,4-DHAQ, 1,4-AHAQ and 1,4-DAAQ dimers show a faster oxidation of the fully reduced form ([2,2]) followed by a slower oxidation of the mixed-valence form 9[2,3]). No mechanism could be determined for the faster oxidation. However, the slower oxidation appeared to be first order in both dimer and S2O82-, and involved ion pairing. Kip was determined to be 13 for the 3 +,2- ion pair. Values for ket were found to parallel the second ruthenium oxidation potential for the dimers, and were found to be 6 X 10-4, 8 X 10-4 and 1.1 X 10-2 M-1 s-1 for the 1,4-DHAQ, 1,4- AHAQ and 1,4-DAAQ dimers, respectively, at 25C....
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