Perfluoroalkylation Of Porphyrins: Synthesis And Reactions Of Beta-perfluoro-alkyltetraarylporphyrins

Porphyrins dominate great application in various scientific fields such as biomimetic models for photosynthesis, catalysis,supramolecular chemistry and medical applications, such as photodynamic therapy. Introduction of fluorine or fluoroalkyl group at periphery of porphyrins has deep effect on the properties of the ligands. This paper, including four parts, is mainly about the synthesis of the p-perfluoroalkyltetraarylporphyrins.In the first part of the paper, we wanted to synthesize the β-trifromethyltetraphenylporphyrins by trifluoromathylation of the beta-bromoporphyrins, but the desired compounds were not obtained.In the second part of our paper, we do some research on the fluoroalkylation of tetraarylporphyrin. Some interesting results were obtained. It was found that sulfinatodehalogenation method is most suitable to introduce perfluoroalkyl group onto β, β-double carbon-carbon bond of meso-tetraarylporphyrins, i.e., treatment of meso-tetraphenylporphyrin (H2TPP), with perfluoroalkyl iodide(RfI) in the presence of Na2S204 and NaHCO3 in a mixture solvent of DMSO/CH2Cl2 at room temperature for several hours gave the corresponding β-perfluoroalkyl porphyrins in 20-40% yields. Notally, at 30-40℃, the most suitable reaction temperature, only carbon iodine bond in w -chloroper- fluorobutyl iodides(3₄b) was cleaved while carbon-chlorine bond intact. Following the mechanism was investigated. In order to understand the reaction mechanism, some inhibition experiments were carried out. Addition of single election-transfer scavenger, i.e., p-dinitobenzene(20mol%) or free radical inhibitor i.e.,hydroquione(20mol%) to the reaction mixture completely inhibited the reaction at the same conditions. Base on the experiments we imaged that the perfluoroalkyl radical may be involved.In third part of our paper, some derivatives of 2-perfluoroalkyl- porphyrins were synthesized. The zinc and copper 2-fluoroalky 1-5,10,15,20- tetraarylporphyrin complexes can be readily prepared in nearly quantatively from the reaction of the corresponding porphyrins with zinc or copper acetate in CH2Cl2-CH3OH at room temperature for 30 minsIn order to further functionalize the 6-fluoroalkyltetraarylporphyrins, electrophinic substitutions on the antipodal β,β-double bond were first investigated, i.e.,bromination and nitronation of the fluoroalkyltetraarylporphyirns were carried out.In the third part of the paper fluoroalkylation of metalloporphyrins were also carried out. And the 2-perfluoroalkyl-metalloporphyrins can also be prepared from the corresponding metalloporphyrins.Finally, based on our above results, in the case of the free base , we thought that the tautomer of 2-fluoroalkyl-5,10,15,20-tetraphenyl 22-H,24-H porphyrin, in which there is an isolated fluoroalkyl ethene system, is heavily more favored in solution at tautomeric equilibrium.