Constructing a Nonfluorescent Conformation of AIEgen: A Tetraphenylethene Embedded in the Calix[4]arene's Skeleton.
Two novel 1,1-diphenylmethylidene decorated calix[4]arenes, (Calix-DPE(OCH3)4and Calix-DPE(OH)4), were designed and prepared. The tetraphenylethene (TPE) unit is embedded in the calix[4]arenes skeleton, so the conformation of tetraphenylethene unit is significantly affected by the conformation of calix[4]arene. Unlike the Calix-DPE(OCH3)4, the Calix-DPE(OH)4does not show the aggregation-induced emission (AIE) phenomena in solution or the crystal state because of the presence of intramolecular hydrogen bonding, which leads to a cone conformation for the calix[4]arene skeleton in which the embedded phenyl rings of the TPE have to take an almost perpendicular configuration to the C=C bond. This result provides direct evidence that the maximal cross-chromophore π-conjugation within the tetraphenylethene is one of the prerequisites of switching on its AIE. This offers the possibility of switching the emission of TPE by conformation changes.
Marine College, Shandong University at Weihai, 180 Wenhua Xilu, Weihai, Shandong, 264209, P. R. China.
Bin
B
Han
Marine College, Shandong University at Weihai, 180 Wenhua Xilu, Weihai, Shandong, 264209, P. R. China.
Xi
X
Wang
Marine College, Shandong University at Weihai, 180 Wenhua Xilu, Weihai, Shandong, 264209, P. R. China.
Yan
Y
Gao
Marine College, Shandong University at Weihai, 180 Wenhua Xilu, Weihai, Shandong, 264209, P. R. China. ming_bai@sdu.edu.cn.
Ming
M
Bai
calix[4]arene; configuration; dyes/pigments; fluorescence; tetraphenylethene