Substituent Effect on the Optoelectronic Properties of Alternating Fluorene-Cyclopentadithiophene Copolymers was written by Pal, Bikash;Yen, Wei-Che;Yang, Jye-Shane;Chao, Chi-Yang;Hung, Ying-Chieh;Lin, Shiang-Tai;Chuang, Chia-Hao;Chen, Chun-Wei;Su, Wei-Fang. And the article was included in Macromolecules (Washington, DC, United States) in 2008.COA of Formula: C9H4I2OS2 This article mentions the following:
A novel series of soluble alternating conjugated copolymers, comprised of 9,9-dihexylfluorene and cyclopentadithiophenes (P1-P5), were synthesized via Pd-catalyzed Suzuki coupling reaction in good yields. The UV-vis absorption spectra, fluorescence spectra, fluorescence quantum yields, and cyclic voltammograms of P1-P5 are also reported. The P2 and P3 with electron-donating non-π-substituents (ethylenedioxy and propylenedioxy bridges the 3,3-positions of the thiophene groups) display high fluorescence quantum yields and red-shifted absorption as compared with nonsubstituted P1. However, the P4 and P5 are weakly fluorescent and exhibit blue-shifted absorption which are due to the presence of electron-withdrawing π-substituents (carbonyl and dicyanoethenyl). The behavior of P4 and P5 can be attributed to the significant electronic coupling between the π-substituents and the conjugated polymer backbone that leads to a less allowed optical transition between the ground and the lowest excited state, resembling the meta conjugation effect in phenylene-derived conjugated π-systems. This argument is supported by MO distribution calculations In the experiment, the researchers used many compounds, for example, Bis(2-iodothiophen-3-yl)methanone (cas: 474416-61-0COA of Formula: C9H4I2OS2).
Bis(2-iodothiophen-3-yl)methanone (cas: 474416-61-0) belongs to iodide derivatives. Iodide-containing intermediates are common in organic synthesis, because of the easy formation and cleavage of the C–I bond. Polyiodoorganic compounds are sometimes employed as X-ray contrast agents, in fluoroscopy, a type of medical imaging. This application exploits the X-ray absorbing ability of the heavy iodine nucleus.COA of Formula: C9H4I2OS2
Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com