A number of novel lanthanide (Gd³⁺, Sm³⁺, and Tb³⁺) complexes of the 1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole] (spiropyran; SP), a widely studied molecular photoswitch, were investigated. Comparative spectroscopic (absorption and fluorescence) and kinetic investigations of the stimulated photochromic and solvatochromic behavior were carried out in different media. SP embedded in a rigid thin film of poly(methylmethacrylate) might be exploited profitably as an optical sensor for the identification of a solvent's nature. Furthermore, thermodynamic parameters, in particular, Gibbs’ free energy change (ΔG°), were derived using density functional theory quantum chemical calculations with the SP and merocyanine coloured form. The model used was the B3LYP/6-31G(d,p)/SCRF = (SMD, solvent) and its time-dependent extension procedure was used to quantitatively explain the structural isomerization in response to a variety of stimuli, such as light, solvent nature, lanthanide(III) ions, and macromolecular support. These findings might be useful for the design of photoswitchable and energy transfer materials and their related fields.

中文翻译：

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螺吡喃光电开关和传感器的镧系元素络合物：光谱研究和计算模型

1'，3'-二氢-8-甲氧基-1'，3'，3'-三甲基-6-硝基螺[2]的许多新型镧系元素（Gd ³⁺，Sm ³⁺和Tb ³⁺）配合物研究了被广泛研究的分子光开关H -1-苯并吡喃-2,2'-（2 H）-吲哚]（spiropyran; SP）。在不同的介质中对激发的光致变色和溶剂变色行为进行了比较光谱（吸收和荧光）和动力学研究。嵌入聚甲基丙烯酸甲酯硬质薄膜中的SP可能会被有利地用作光学溶剂，以识别溶剂的性质。此外，热力学参数，尤其是吉布斯的自由能变化（ΔG°），是通过使用SP和部花青有色形式的密度泛函理论量子化学计算得出的。所使用的模型为B3LYP / 6-31G（d，p）/ SCRF =（SMD，溶剂），并使用其随时间变化的扩展程序来定量解释响应各种刺激（例如光）的结构异构化溶剂性质，镧系元素（III）离子和大分子载体。这些发现对于光开关和能量转移材料及其相关领域的设计可能是有用的。