A DFT calculations are carried out at UB3LYP/6-311＋ ＋G （3df, 2p） levels of theory to study electrocyclic thermal cleavage of four （R） derivatives of unsaturated bicyclic diaziridines, Ix-R, to produce correspond...A DFT calculations are carried out at UB3LYP/6-311＋ ＋G （3df, 2p） levels of theory to study electrocyclic thermal cleavage of four （R） derivatives of unsaturated bicyclic diaziridines, Ix-R, to produce corresponding （Z） and （E） azomethine imides （2X-Z, 2X-E, 3X-Z and 3X-E）, where X=H, Me, t-Bu and Ph. Cleavage of 1X-R series to form the most stable 3X-Z product, （path 2） is found the favored procedure because of delocalized negative charge on five atoms and lower steric effect in related transition state. According to IRC calculations in paths 1 and 2, C6--N1 bond is cleaved before the rate determinating step （transition state）. The stability of unsaturated bicyclic diaziridines and their corresponding （Z） and （E） azomethine imides is in the following order in gas phase and chloroform, tetrahydrofuran, and acetone solvents： 3X-Z〈3X-F〈2X-Z 〈2X-E 〈 1X-R 〈 1X-S.展开更多
5, 10, 15-Triphenyl-20-{2-[alpha-(adenine-9) acetylamino]} phenyl porphyrin (1), 5,10,15-triphenyl-20-{2-[alpha-(cytosine-]}acetylamino]} phenyl porphyrin (2), 5, 10, 15-triphenyl-20-{4-[alpha(cytosine-1)ethoxy]} I I ...5, 10, 15-Triphenyl-20-{2-[alpha-(adenine-9) acetylamino]} phenyl porphyrin (1), 5,10,15-triphenyl-20-{2-[alpha-(cytosine-]}acetylamino]} phenyl porphyrin (2), 5, 10, 15-triphenyl-20-{4-[alpha(cytosine-1)ethoxy]} I I phenyl porphyrin (3) and their zinc complexes Zn-1, Zn-2 and Zn-3 have been prepared and characterized by H-1 NMR spectra, elemental analyses, electronic absorption spectra and mass spectra (FAB). Intramolecular pi-pi interactions and intramolecular metal-pi interaction for 1, 2, Zn-1, and Zn-2 have been investigated by several methods. H-1 NMR studies demonstrate that the porphyrin pi-system in 1 and 2 is parallel to the adenine and the cytosine aromatic ring, respectively. The electronic absorption spectral properties of free porphyrin derivatives and their zinc complexes have been compared with those of H2TPP and ZnTPP. The results show that the UV-vis spectra of 1 and 2 are the same as that of H2TPP, whereas the spectra of their zinc complexes show 7 nm red shifts of the Soret bands compared to that of ZnTPP. The emission spectra of Zn-1 and Zn-2 are independent of excitation wavelength. From combination of the evidence of absorption and emission spectra it is suggested the existence of intramolecular metal-pi interaction in Zn-1 and Zn-2. The results of conformational analysis agreed quite nicely with that of experiments, thus it was further to validate the experimental conclusions.展开更多
文摘A DFT calculations are carried out at UB3LYP/6-311＋ ＋G （3df, 2p） levels of theory to study electrocyclic thermal cleavage of four （R） derivatives of unsaturated bicyclic diaziridines, Ix-R, to produce corresponding （Z） and （E） azomethine imides （2X-Z, 2X-E, 3X-Z and 3X-E）, where X=H, Me, t-Bu and Ph. Cleavage of 1X-R series to form the most stable 3X-Z product, （path 2） is found the favored procedure because of delocalized negative charge on five atoms and lower steric effect in related transition state. According to IRC calculations in paths 1 and 2, C6--N1 bond is cleaved before the rate determinating step （transition state）. The stability of unsaturated bicyclic diaziridines and their corresponding （Z） and （E） azomethine imides is in the following order in gas phase and chloroform, tetrahydrofuran, and acetone solvents： 3X-Z〈3X-F〈2X-Z 〈2X-E 〈 1X-R 〈 1X-S.
文摘5, 10, 15-Triphenyl-20-{2-[alpha-(adenine-9) acetylamino]} phenyl porphyrin (1), 5,10,15-triphenyl-20-{2-[alpha-(cytosine-]}acetylamino]} phenyl porphyrin (2), 5, 10, 15-triphenyl-20-{4-[alpha(cytosine-1)ethoxy]} I I phenyl porphyrin (3) and their zinc complexes Zn-1, Zn-2 and Zn-3 have been prepared and characterized by H-1 NMR spectra, elemental analyses, electronic absorption spectra and mass spectra (FAB). Intramolecular pi-pi interactions and intramolecular metal-pi interaction for 1, 2, Zn-1, and Zn-2 have been investigated by several methods. H-1 NMR studies demonstrate that the porphyrin pi-system in 1 and 2 is parallel to the adenine and the cytosine aromatic ring, respectively. The electronic absorption spectral properties of free porphyrin derivatives and their zinc complexes have been compared with those of H2TPP and ZnTPP. The results show that the UV-vis spectra of 1 and 2 are the same as that of H2TPP, whereas the spectra of their zinc complexes show 7 nm red shifts of the Soret bands compared to that of ZnTPP. The emission spectra of Zn-1 and Zn-2 are independent of excitation wavelength. From combination of the evidence of absorption and emission spectra it is suggested the existence of intramolecular metal-pi interaction in Zn-1 and Zn-2. The results of conformational analysis agreed quite nicely with that of experiments, thus it was further to validate the experimental conclusions.
