Intramolecular Relaxation Dynamics Mediated by Solvent-Solute Interactions of Substituted Fluorene Derivatives. Solute Structural Dependence.

Several fluorene derivatives exhibit excited-state reactivity and relaxation dynamics that remain to be understood fully. We report here the spectral relaxation dynamics of two fluorene derivatives to evaluate the role of structural modification in the intramolecular relaxation dynamics and intermolecular interactions that characterize this family of chromophores. We have examined the time-resolved spectral relaxation dynamics of two compounds, NCy-FR0 and MK-FR0, in protic and aprotic solvents using steady-state and time-resolved emission spectroscopy and quantum chemical computations. Both compounds exhibit spectral relaxation characteristics similar to those seen in FR0, indicating that hydrogen bonding interactions between the chromophore and solvent protons play a significant role in determining the relaxation pathways available to three excited electronic states.

几种芴衍生物表现出激发态反应性和弛豫动力学，这些仍有待充分理解。我们在此报道了两种芴衍生物的光谱弛豫动力学，以评估结构修饰在分子内弛豫动力学以及表征这一类发色团的分子间相互作用中所起的作用。我们使用稳态和时间分辨发射光谱以及量子化学计算，研究了两种化合物（NCy - FR0和MK - FR0）在质子性和非质子性溶剂中的时间分辨光谱弛豫动力学。这两种化合物都表现出与FR0相似的光谱弛豫特性，这表明发色团与溶剂质子之间的氢键相互作用在决定三个激发电子态可利用的弛豫途径方面起着重要作用。