Carbon-centered dendritic radicals: photoinduced reaction of poly(benzyl ether) dendrons sigma-bonded to a rhodium(III) porphyrin focal core

Poly(benzyl ether) dendrons sigma -bonded by the focal dialkoxybenzyl unit to a rhodium(III) porphyrin functionality (1-Ln, n=1, 3-5) were synthesized as novel carbon-centered free radical equivalents. Upon excitation with vi sible light in a carbon monoxide atmosphere, 1-Ln (n = 1, 3-5) underwent ho molysis at the alkyl-rhodium bond to give the corresponding acylrhodium spe cies 2-Ln (n=1, 3-5), where the consumption rate of l-Ln was dependent on t he generation number of the dendron unit. In particular, 1-L5 bearing the l argest dendron unit was much reluctant to undergo photochemical reactions. (C) 2001 Elsevier Science Ltd. All rights reserved.