Design of a fluorescent host for monitoring multiple hydrogen-bonding interaction directly by intramolecular charge-transfer emission
作者:Koji Araki、Ken-ichi Tada、Masanori Abe、Toshiki Mutai
DOI:10.1039/a800813b
日期:——
The hosts 2-dodecanamido-4-methyl-N-[4-(dimethylamino)phenyl]quinoline-7-carboxamide 1 and 2-dodecanamido-4-methyl-N-(4-methoxyphenyl)quinoline-7-carboxamide 2 bearing an aromatic amide unit exhibit an anomalous fluorescence with a large Stokes shift at around 500–600 nm (LW emission) due to an intramolecular charge-transfer (ICT) process. The guests 3-ethyl-3-methylglutarimide (bemegride) 4 and 1-methyluracil 5 are associated with the hosts by forming three hydrogen bonds, and LW emission of the hosts largely increase. On the other hand, the guest 3-methyluracil 6 does not affect the emission of the hosts at all, though formation of two hydrogen bonds with the hosts is confirmed by 1H NMR measurement. It is concluded that the hosts 1 and 2 can selectively detect the guests 4 and 5 that form hydrogen bonds both at the quinoline ring nitrogen and the amide proton (Hα) of the hosts simultaneously to affect rotation of the amide bond.
带有芳香酰胺单元的 2-十二酰胺基-4-甲基-N-[4-(二甲基氨基)苯基]喹啉-7-甲酰胺 1 和 2-十二酰胺基-4-甲基-N-(4-甲氧基苯基)喹啉-7-甲酰胺 2 的宿主由于分子内电荷转移(ICT)过程而在 500-600 nm 处(LW 发射)显示出较大的斯托克斯偏移的异常荧光。客体 3-ethyl-3-methylglutarimide (bemegride) 4 和 1-methyluracil 5 通过形成三个氢键与宿主结合,宿主的 LW 发射大大增加。另一方面,虽然 1H NMR 测量证实 3-甲基尿嘧啶 6 与宿主形成了两个氢键,但它完全不影响宿主的发射。结论是宿主 1 和 2 可以选择性地探测客体 4 和 5,客体 4 和 5 同时在宿主的喹啉环氮和酰胺质子(Hα)上形成氢键,从而影响酰胺键的旋转。