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Tetraphenylporphyrin dimers and their derivatives

University of British Columbia

Tetraphenylporphine (TPP) and its para-methyl derivative have been synthesized by direct reaction of pyrrole with the corresponding aldehyde. The synthesis of two unsymmetrically substituted tetraarylporphyrins is reported. The compounds prepared are' 5-(4-hydroxypheny1) -10,15,20-tritolyIporphyrin and 5-(4-hydroxypheny1)-10, 15,20-triphenyIporphyrin. The sy thesis of covalently linked porphyrin dimers, joined via ether linkages, is described. High yields of the tetraaryIporphyrin dimers were obtained by the reaction of the bi-functional1,6-ditosyloxyhexane with phenolic porphyrins such as 5-(4-hydroxypheny1)-10,15,20-tritoly1-porphyrin. The dimeric porphyrins were then chromatographically separated from the unreacted monomericLporphyrins. The reduction of the porphyrins(monomers and dimers) has been carried out using the standard diimide precursor, p-toluenesulfonylhydrazine. We have been able to demonstrate that the most efficient chlorin preparation involves the diimide reduction of a tetraaryIporphyrin to the corresponding bacteriochlorin, followed by the addition of the "high potential quinone" DDQ, to dehydro-genate the bacteriochlorin. A detailed study of the absorption spectra of these chlorins and bacteriochlorins was undertaken. Zinc metallo-derivatives of the porphyrins, chlorins and bacteriochlorins were prepared by the reaction of the free bases with zinc acetate in dry pyridine. An attempt was made to synthesize tetra-meso-[p, p ' - ( 3, 3 '-phenoxypropoxypheny1)]-strati-bis porphyrin (Compound XX), a novel cyclophane system composed of two opposed, co-axial porphyrin rings, rigidly held together by peripheral ether linkages. The synthesis was attempted by construction of a second porphyrin ring on top of a pre-existing one, by way of the condensation of four pyrroles with a tetraaldehyde, derivative of tetraphenyl-porphyrin, under high dilution conditions. The last reaction step was unsuccessful. The structures and purity of the intermediate compounds leading to the strati-bis-porphyrin were established by mass spectroscopy and proton n.m.r. spectroscopy.

Text

2010-03-11

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http://hdl.handle.net/2429/21765

Chemistry

University of British Columbia

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