3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weig...3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weight poly(thienylacetylenes) (2) (M-w up to 602000) in high yields (up to 100%). Light transmission spectra of THF solutions of 2 continuously red-shift with increasing concentration. The concentratochromism shows a logarithmic concentration dependence; that is, the optical transitions of 2 are predictably tunable by simply changing their concentrations.展开更多
Light transmission spectra of THF solutions of poly (C-60-co-methyl methacrylate)s and poly(C-60-co-styrene)s continuously red-shift with increasing concentration. Formation of fullerene nanoclusters may be responsibl...Light transmission spectra of THF solutions of poly (C-60-co-methyl methacrylate)s and poly(C-60-co-styrene)s continuously red-shift with increasing concentration. Formation of fullerene nanoclusters may be responsible for the unusual spectral shift, with concentration. It has long been scientists' dream to ''tune'' material's properties by simple means, and the C-60-containing polymers represent such a group of novel materials whose optical properties are predictably and reversibly tunable by a simple change in concentration.展开更多
基金This work was in part supported by the Earmarked Research Grants of the Hong Kong Research Grants Council (HKUST597/95P and CUHK77/931).
文摘3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weight poly(thienylacetylenes) (2) (M-w up to 602000) in high yields (up to 100%). Light transmission spectra of THF solutions of 2 continuously red-shift with increasing concentration. The concentratochromism shows a logarithmic concentration dependence; that is, the optical transitions of 2 are predictably tunable by simply changing their concentrations.
基金This work was in part supported by a grant from the Hong Kong Government Research Grants Council(DAG96/97.SC11)
文摘Light transmission spectra of THF solutions of poly (C-60-co-methyl methacrylate)s and poly(C-60-co-styrene)s continuously red-shift with increasing concentration. Formation of fullerene nanoclusters may be responsible for the unusual spectral shift, with concentration. It has long been scientists' dream to ''tune'' material's properties by simple means, and the C-60-containing polymers represent such a group of novel materials whose optical properties are predictably and reversibly tunable by a simple change in concentration.
