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

Abstract

Poly(benzyl ether) dendrons σ-bonded by the focal dialkoxybenzyl unit to a rhodium(III) porphyrin functionality ( 1 -L n, n=1, 3–5) were synthesized as novel carbon-centered free radical equivalents. Upon excitation with visible light in a carbon monoxide atmosphere, 1 -L n ( n=1, 3–5) underwent homolysis at the alkylrhodium bond to give the corresponding acylrhodium species 2 -L n ( n=1, 3–5), where the consumption rate of 1 -L n was dependent on the generation number of the dendron unit. In particular, 1 -L5 bearing the largest dendron unit was much reluctant to undergo photochemical reactions.