TY - JOUR
T1 - Dendritic structure having a potential gradient
T2 - New synthesis and properties of carbazole dendrimers
AU - Albrecht, Ken
AU - Yamamoto, Kimihisa
PY - 2009/2/18
Y1 - 2009/2/18
N2 - A new synthetic route for carbazole dendrimers was discovered using the copper-catalyzed N-arylation reaction. This synthetic route allowed synthesizing the fourth generation carbazole dendrimer and several derivatives for the first time. The crystal structure, Mark-Houwink-Sakurada plots, and UV-vis and fluorescence studies showed that the dendritic carbazole backbone has a rigid and highly twisted structure. From the measurement of the redox potential of the ferrocene derivatives, the IR spectra of the benzophenone derivatives, and complexation behavior of the phenylazomethine derivatives, the inductive electron-withdrawing effect of the carbazole dendron was revealed. This suggested that the summation of this electron withdrawal from each layer may produce a potential gradient such that the outer layer is electron-rich and the inner layer is electron-poor in the carbazole dendron. By assignment of the 1H and 13C NMR spectra of the dendron, the existence of this kind of potential gradient was proved. Overall, these data show the π-polarization substituent effect of the carbazole unit, and their summation determines the potential gradient in the repeating dendritic structure of the carbazole dendrimer.
AB - A new synthetic route for carbazole dendrimers was discovered using the copper-catalyzed N-arylation reaction. This synthetic route allowed synthesizing the fourth generation carbazole dendrimer and several derivatives for the first time. The crystal structure, Mark-Houwink-Sakurada plots, and UV-vis and fluorescence studies showed that the dendritic carbazole backbone has a rigid and highly twisted structure. From the measurement of the redox potential of the ferrocene derivatives, the IR spectra of the benzophenone derivatives, and complexation behavior of the phenylazomethine derivatives, the inductive electron-withdrawing effect of the carbazole dendron was revealed. This suggested that the summation of this electron withdrawal from each layer may produce a potential gradient such that the outer layer is electron-rich and the inner layer is electron-poor in the carbazole dendron. By assignment of the 1H and 13C NMR spectra of the dendron, the existence of this kind of potential gradient was proved. Overall, these data show the π-polarization substituent effect of the carbazole unit, and their summation determines the potential gradient in the repeating dendritic structure of the carbazole dendrimer.
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U2 - 10.1021/ja807312e
DO - 10.1021/ja807312e
M3 - Article
C2 - 19175324
AN - SCOPUS:67849106905
VL - 131
SP - 2244
EP - 2251
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 6
ER -