Two dendrimers, D1 and D2, containing the cationic iridium complexes (C1 and C2) as cores and truxene-functionalized chromophores as the branches, have been developed by a convergent synthetic strategy. The cationic complexes employ 3-(pyridin-2-yl)-1H-1,2,4-triazole and 2-(pyridin-2-yl)-benzimidazole derivatives as the ancillary ligands. To avoid the change in emission colour arising from the iridium complex, the conjugation between the dendron and the ligand is decoupled by separating them using the alkyl chain. An investigation of their photoluminescent features reveals that efficient energy transfer happens from the dendrons to the core in the solid state. Likewise, the charged dendritic structure is demonstrated to be an efficient method to improve the compatibility between the polar charged iridium complexes and typical hydrophobic hosts with the additional benefit of excellent solution processability. Both dendrimers exhibit strong solvatochromic behaviours in solvents and exclusive green and yellow-orange light in the solid state.
我们采用聚合合成策略开发出了两种树枝状聚合物 D1 和 D2,它们以阳离子铱络合物(C1 和 C2)为核心,以三烯功能化发色团为分支。阳离子配合物采用 3-(吡啶-2-基)-1H-1,2,4-三唑和 2-(吡啶-2-基)-苯并咪唑衍生物作为辅助配体。为了避免铱配合物引起的发射颜色变化,树枝状化合物和配体之间的共轭作用通过使用烷基链进行分离而解除。对其光致发光特征的研究表明,在固态下,能量从树枝状结构有效地传递到核心。同样,带电树枝状结构也被证明是改善极性带电铱复合物与典型疏水性宿主之间相容性的有效方法,而且还具有优异的溶液加工性。这两种树枝状聚合物在溶剂中都表现出强烈的溶解变色行为,在固态下则表现出独有的绿色和橘黄色光。