Synthesis and Characterization of New porphyrins and Porphyrin Derivatives with Fluorine.

以2-（2-三氟-1-羟乙基）吡咯为原料，经氧化环化得到5，10，15，20-四（三氟甲基）卟啉1，再与碘化三氟甲基在DMF中进行光化学三氟甲基化反应，得到内消旋-（三氟甲基）八乙基卟啉5.类似地，以中等产率获得δ-（三氟甲基）-八乙基二氢卟啉6和meso-（三氟甲基）mesoporphyrin IX二甲酯。后<19>一种产物的~ 1H-NMR和~ 1F-NMR表明形成了四种区域异构体9- 12。由于meso-三氟甲基的空间位阻和电子效应，这些化合物显示出各种不寻常的性质。电化学研究和分子轨道能量计算表明，1、5和6的HOMO和LUMO比三氟甲基取代的化合物明显稳定.此外，对于5，LUMO的稳定性要大得多。这种差异可归因于乙基和三氟甲基之间的相互作用导致的卟啉环的部分变形。

5, 10, 15, 20-Tetrakis (trifluoromethyl) porphyrin, 1, was obtained by oxidative cyclization of 2-(2-trifluoro-1-hydroxyethyl) pyrrole in moderate yield.Meso-(trifluoromethyl) octaethylporphyrin, 5, was readily prepared by photochemical trifluoromethylation of octaethylporphyrin with trifluoromethyl iodide in DMF.No pertrifluoromethylation products have been detected in the present reaction. Similarly, δ-(trifluoromethyl)-octaethylchlorin, 6, and meso-(trifluoromethyl) mesoporphyrin IX dimethyl ester were obtained in moderate yields. ^1H-NMR and ^<19>F-NMR of the latter products indicated formation the four regioisomers, 9-12.These compounds showed a variety of unusual properties due to steric constrain and electronic effect of the meso-trifluoromethyl group. Both electrochemical studies and energy calculations of molecular orbitals indicated that the HOMO and LUMO of 1, 5, and 6 were markedly stabilized than those of trifluoromethyl group unsubstituted compounds. Moreover, for 5 the stabilization is much greater for the LUMO.This difference is attributable to the partial distortion of the porphyrin ring by interaction between the ethyl and trifluoromethyl groups.