Characterization of Pd-β-Cyclodextrin Colloids as Catalysts in the Photosensitized Reduction of Bicarbonate to Formate

Itamar Willner*, Daniel Mandler

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

Photosensitized reduction of bicarbonate. HCO3-, to formate. HCO2-, proceeds in an aqueous system composed of deazariboflavin, dRFl (1), 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 process proceeds with a quantum efficiency, ϕ = 1.1. Kinetic characterization of the Pd-β-CD catalyst activity reveals the presence of active sites for bicarbonate activation and reduction as well as catalytic sites for H2 evolution. The HCO3- activation sites are specifically inhibited by thiols. The catalytic reduction of HCO3- to HCO2- and the respective inhibition processes exhibit enzyme-like kinetic properties. The Pd-β-CD colloid shows reversible activities and effects the reduction of MV2+ by formate. Kinetic characterization of the catalyzed reduction of HCO3- to HCO2- and the reverse oxidation of HCO2- provides a sequential mechanism for the reactions.

Original languageAmerican English
Pages (from-to)1330-1336
Number of pages7
JournalJournal of the American Chemical Society
Volume111
Issue number4
DOIs
StatePublished - Feb 1989

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