Excited state dynamics of trinary star-shaped dendritic compounds with triphenylamine arms and different cores were studied by means of time-resolved fluorescence and transient absorption. Under optical excitation, nonpolar C₃ symmetry molecules form polar excited states localized on one of the molecular substituents. Conformational excited state stabilization of molecules with an electron-accepting core causes a formation of twisted internal charge transfer (TICT) states in polar solvents. A low transition dipole moment from TICT state to the ground state causes very weak fluorescence of those compounds and strong dependence on the solvent polarity. The compound formed from the triphenylamine central core and identical arms also experiences excited state twisting, however, weakly sensitive to the solvent polarity.

中文翻译：

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三元星形三苯胺基化合物中的扭曲的分子内电荷转移态

通过时间分辨荧光和瞬态吸收研究了具有三苯胺臂和不同核的三叉星形树枝状化合物的激发态动力学。在光激发下，非极性C ₃对称分子形成位于分子取代基之一上的极性激发态。具有电子接受核的分子的构象激发态稳定化会在极性溶剂中形成扭曲的内部电荷转移（TICT）状态。从TICT态到基态的低跃迁偶极矩会导致这些化合物的荧光非常弱，并强烈依赖于溶剂极性。由三苯胺中心核和相同臂形成的化合物也经历激发态扭曲，但是对溶剂极性敏感。