Send to

Choose Destination
See comment in PubMed Commons below
ACS Catal. 2011 May 18;1(7):764-771.

Ligand Fluorination to Optimize Preferential Oxidation (PROX) of Carbon Monoxide by Water-Soluble Rhodium Porphyrins.

Author information

†Department of Chemistry and Nebraska Center for Materials and Nanoscience University of Nebraska, Lincoln, NE 68588-0304.


Catalytic, low temperature preferential oxidation (PROX) of carbon monoxide by aqueous [5,10,15,20-tetrakis(4-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (1[Rh(III)]) and [5,10,15,20-tetrakis(3-sulfonato-2,6-difluorophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (2[Rh(III)]) is reported. The PROX reaction occurs at ambient temperature in buffered (4 ≤ pH ≤ 13) aqueous solutions. Fluorination on the porphyrin periphery is shown to increase the CO PROX reaction rate, shift the metal centered redox potentials, and acidify ligated water molecules. Most importantly, β-fluorination increases the acidity of the rhodium hydride complex (pK(a) = 2.2 ± 0.2 for 2[Rh-D]); the dramatically increased acidity of the Rh(III) hydride complex precludes proton reduction and hydrogen activation near neutral pH, thereby permitting oxidation of CO to be unaffected by the presence of H(2). This new fluorinated water-soluble rhodium porphyrin-based homogenous catalyst system permits preferential oxidation of carbon monoxide in hydrogen gas streams at 308 °K using dioxygen or a sacrificial electron acceptor (indigo carmine) as the terminal oxidant.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for PubMed Central
    Loading ...
    Support Center