CIDHP-Effects in Photoreaction of Substituted Benzoquinonewith Tetraphenylporphyrin

摘要

The photoreactions of quinones with the electron donors and hydrogen atoms have been previously described in details [1]. In this report we considered the photolysis of 2,6-dimethyl- (I), 2,6-di-tert-butyl-(II) and 2,6-diphenyl-para-benzoquinones (III) with tetraphenylporphyrin IV in deuterochloroform directly in the NMR spectrometer probe with simultaneous recording of the ~1HNMR spectra. The ~1HNMR spectra of the reaction mixture of tetraphenylporphyrin IV with quinones I and II under irradiation did not differ from the spectra recorded in the dark except for some signal broadening. The CIDNP (Chemically Inducedsignal. In the initial quinone we observed the positive polarization on the carbonyl carbon atom (δ_(c) 190 ppm) and the negative polarization on the meta-carbon atoms (δ_(c) 139 ppm). The carbon nuclei in the meso-positions of the porphyrin ring (δ_(c) 122 ppm) were negatively polarized. The polarization of the carbon nuclei in the substituted pyrrole ring was not detected. Thus, the dercalization of the electron density is likely to occur on the inner pyrrole ring.