meta-substituted phenyl-cored dendrimers were predominantly responsible for absorption and that excitons were localized to the “arms” without any electronic coupling between them, but also introduced the caveat that there was a minimum of two contiguous thiophene rings required for strict exciton localization to the arms. The oxidation potentials of the compounds in solution ranged from 0.9 to 1.6 V and were
在一系列间位取代的
噻吩苯(T n)2 C 6 H 4和(T n)3 C 6 H 3(n = 1,2; T 1 = 2-
噻吩基; T 2 = 2,2'-bithien-5-基)。PdCl 2催化的熊田偶联反应就便利性,选择性和收率而言,发现合适的
噻吩基格氏与1,3-或1,3,5-
溴或
碘苯之间的(dppf)是最可靠的(dppf = 1,1'-bis(
二苯基膦)
二茂铁)。这些条件也使混合的(
噻吩基)(卤)苯,(T n)C 6 H 3 X 2和(T n)2 C 6 H 3 X(X = Br,I)最优化合成。后者的
溴化物可在随后的Stille,Sonogashira或Kumada反应中进一步完善,以提供在第三个间位(T n)2 C 6带有供电子或吸电子基团的双(
噻吩基)化合物H 3 R(R = Ph,p -MeOC 6 H 4,p -FC 6 H 4 ; n = 1,2)和(T 1)2 C 6 H 3