| Summary: | 碩士 === 國立臺灣大學 === 化學系 === 85 === Water-soluble chromium(III) meso-tetrakis(3-sulfonatomesityl) porphyrin
(CrIIITSMP)was synthesized and the ortho-methyl groups in
meso-substituents have provided good sterical protection for the
meso-carbons upon radical cation or anion formation. The pKa1 and
pKa2 for (H2O)2CrIIITSMP are 8.5 and 11.6, respectively. The
electrochemistry and spectroelectrochemistry of CrTSMP have been
studied. In a pH 3.2 buffer solution, two distinct one-electron transfer
steps could be observed by spectroelectrochemical method and both
processes are reversible. The oxidation states are CrIIITSMP+* and
O=CrIVTSMP+*, respectively. At high pH values, the spectra belong to
O=CrIVTSMP﹑O=CrIVTSMP+* and O=CrVTSMP could be observed.
The pKa for O=CrVTSMP is 12.0, which was determined by chemical
oxidation coupled with pH titration. Cyclo-pent-2-ene-1-acetic acid can
be electrocatalytically oxidized to enone by CrTSMP and the optimal
condition is reached in pH 7.0 buffer solution.
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