Strati-Bis Porphyrins: A Promising Gauge for Study of Photo-Induced Electron Transfer. Final Summary Report

摘要

The synthesis of a new series of strati-bisporphyrins (sbPs) is reported. The synthesis via the preparation of the first amide-linked sbP, tetra-meso-(m,m' (N-benzyl benzamide)) strati-bisporphyrin, III. This highly symmetric and well defined staked porphyrin dimer of two meso-substituted tetra phenyl porphyrins joined at the meta positions of all eight phenyl groups by four methyl formamide linkages, -CH sub 2 NHCO-. This sbP is being prepared by the de-novo coupling procedure where a second porphyrin ring is constructed upon an initial porphyrin ring by way of the internal condensation of a porphyrin tetraaldehyde with four pyrrole molecules. This is the same general scheme which was successfully used in the synthesis of the first sbP system which had ester linkages. The necessary porphyrin tetraaldehyde for this new amide-linked dimer has already been synthesized. The porphyrin, tetraaldehyde, T-meso (m-N-benzyl(m'-formyl)benzamide) porphyrin, II, was prepared by the acylation of a porphyrin tetraamine with m-chlorocarbonyl benzaldehyde. The porphyrin tetraamine, tetra-meso-(m-aminomethyl-phenyl porphyrin, I, was prepared by the condensation of the shiff-base polymer of m-amino-methyl benzaldehyde with pyrrole in the usual way. The most effective synthetic scheme for the sbP III begins with the preparation of the essential benzaldehydes 5 and 9 by the bromination of commercially available toluene derivatives. The fluorescence and other photophysical properties of these molecules will be studied as purified samples are prepared. 3 figures. (ERA citation 09:048301)