A reversibly transformable chromatic system of the (octaethylporphyrin)-(dihexylbithiophene)-(Lewis base) triads. An evaluation of stereo-electronically controlled effects of dihexylbithiophene and Lewis base on its sensitivity and stability to trifluoroacetic acid
摘要:
The extended pi-electronic conjugation system of the (octaethylporphyrin)-(dihexylbithiophene)-(Lewis base) triads [OEP-DHBTh-LB] exhibits the proton-mediated reversible changes in both H-1 NMR and UV-vis spectra via two-step processes, reflecting the structural features of DHBTh and LB constituents. The spectral changes of OEP-DHBTh-LB with trifluoroacetic acid (TFA) were quantitatively examined by means of H-1 NMR spectral measurement and comparatively analyzed in terms of stereo-electronically controlled effects of DHBTh and LB constituents on its reversibly transformable chromatic system. Successively, based on the minimum amount of TFA necessary for completion of spectral changes at respective steps, the sensitivity and stability of OEP-DHBTh-LB to TFA were evaluated, from the viewpoint of the interactive behavior of the lone pair electrons on N atom in LB with the extended OEP constituent. The present study provides a useful guideline of the molecular design for further sophisticated OEP-based chromatic system with proton-sensing functionality. (C) 2014 Elsevier Ltd. All rights reserved.
Synthesis and Properties of Head-to-head, Head-to-tail, and Tail-to-tail Orientational Isomers of Extended Dihexylbithiophene–Octaethylporphyrin System [OEP–(DHBT)<sub><i>n</i></sub>–OEP] Connected with 1,3-Butadiyne Linkages
An extended π-electronic conjugation system of dihexylbithiophene–octaethylporphyrin [OEP–(DHBT)n–OEP; n = 1–5], all the chromophores in which are connected with the linkage of 1,3-butadiyne (diacetylene), was synthesized by an oxidative cross-coupling reaction of the corresponding terminal acetylenes. Absorption spectral and electrochemical properties of the OEP–(DHBT)n–OEP system were examined. The results proved that the orientation of two 3-hexylthiophene (3HTh) rings of DHBT plays an important role in electronic communications between the two terminal OEP rings.
二己基联噻吩-八乙基卟啉的扩展 π 电子共轭体系 [OEP-(DHBT)n-OEP; n = 1–5],其中所有发色团均与 1,3-丁二炔(丁二炔)键连接,通过相应末端乙炔的氧化交叉偶联反应合成。检查了 OEP-(DHBT)n-OEP 系统的吸收光谱和电化学性质。结果证明DHBT的两个3-己基噻吩(3HTh)环的取向在两个末端OEP环之间的电子通信中起着重要作用。