Marc W. Perkovic

Photochemical fixation of supercritical carbon dioxide: the production of a carboxylic acid from a polyaromatic hydrocarbon

Abstract We present our initial results on the use of supercritical carbon dioxide as both a reactant and as a reaction medium to photo-chemically produce carboxylic acids from polycyclic aromatic hydrocarbons via radical anion intermediates. In the present work, we have found that photolysis of anthracene in supercritical carbon dioxide produces up to 57% yield of 9,10-dihydroanthracene-9-carboxylic acid in the presence of appropriate electron and hydrogen donors. This is in stark contrast to the lack of carboxylic acid formation in conventional non-polar aprotic solvents. Additionally, we have found no evidence that under reaction conditions similar to those necessary for radical anion fixation of carbon dioxide that carbon-centered free radicals produce carboxylic acids.

Photophysical observations on Cr(III) bis-cyclam dimers

Abstract Chromium(III) complexes of the mononucleating cyclam , ([14]aneN 4 )X 2 , and binucleating biscyclam , ([14]aneN 4 ) 2 X 4 , ligands were prepared and their photophysical properties examined. Acido amine cis-monomer and cis,cis-dimer pairs containing X=chloro, bromo and thiocyanato complexes were examined for photophysical manifestations of metal–metal coupling in these saturated macrocyclic systems. UV–vis absorption and emission show anomalous features in the dimer spectra versus their monomer parents for the bromo and thiocyanato complexes in accord with what would be predicted based on a charge transfer mediated exchange process; however, the excited state properties of these molecules show an opposite behavior and thus an interpretation of the observed behavior based on an exchange mechanism is not possible.