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Characterization of palladium-β-cyclodextrin colloids as catalysts in the photosensitized reduction of bicarbonate to formate.

Citation:

Willner I, Mandler D. Characterization of palladium-β-cyclodextrin colloids as catalysts in the photosensitized reduction of bicarbonate to formate. J. Am. Chem. Soc.Journal of the American Chemical Society. 1989;111 (4) :1330 - 6.

Date Published:

1989///

Abstract:

Photosensitized redn. of HCO3- to HCO2- proceeds in an aq. system composed of deazariboflavin, dRFl, as photosensitizer, N,N'-dimethyl-4,4'-bipyridinium, MV2+, as primary electron acceptor, sodium oxalate as sacrificial electron donor, and in the presence of a Pd colloid stabilized by β-cyclodextrin, Pd-β-CD. The reaction proceeds with a quantum efficiency of 1.1. Kinetic characterization of the Pd-β-CD catalyst activity reveals the presence of active sites for bicarbonate activation and redn. as well as catalytic sites for H2 evolution. The HCO3- activation sites are specifically inhibited by thiols. The catalytic redn. of HCO3- to HCO2- and the resp. inhibition processes exhibit enzyme-like kinetic properties. The Pd-β-CD colloid shows reversible activities and effects the redn. of MV2+ by formate. Kinetic characterization of the catalyzed redn. of HCO3- to HCO2- and the reverse oxidn. of HCO2- provides a sequential mechanism for the reactions. [on SciFinder(R)]

Notes:

CAPLUS AN 1989:74636(Journal)