We report herein synthesis, characterization, photophysics, and photo-isomerization behaviors of a new class of heteroleptic Ru(II) complexes incorporating styrylbenzene conjugated terpyridine and 2,6–bis(benzimidazole–2–yl)pyridine ligands. All the complexes display moderately strong luminescence at room temperature with appreciably long lifetime varying in the range between 7.2 and 62.2 ns, depending upon the electronic nature of substituent as well as the solvent. The styrylbenzene moiety induces trans to cis isomerization resulting in remarkable changes in absorption and both steady state and time-resolved luminescence spectral characteristics upon irradiating with UV light. Reversal of cis to trans isomerization were also achieved on interacting with visible light as well as UV light of specific wavelength. Removal of two benzimidazole NH protons from the secondary coordination sphere of the complexes were made possible upon treatment with strong base accompanying with substantial modulation of their absorption and emission spectral properties. Interestingly, rate constant as well as quantum yield of photoisomerization dramatically increases upon deprotonation of the imidazole NH protons. Computational studies employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were also executed for understanding the electronic charge distribution within the complex backbone and appropriate assignment of the observed spectral bands. In addition, observed spectral trend upon NH deprotonation as well as deprotonation-induced photoisomerization processes were also compared with the calculated results.

我们在此报告了新的杂化Ru（II）配合物的合成，表征，光物理和光异构化行为，该配合物结合有苯乙烯基苯共轭的吡啶和2,6-双（苯并咪唑-2-基）吡啶配体。所有的配合物在室温下均显示中等强度的发光，寿命长在7.2至62.2 ns之间，这取决于取代基以及溶剂的电子性质。苯乙烯基苯基部分引起反式至顺式异构化，从而导致吸收率发生显着变化，并在受到紫外线照射后达到稳态和时间分辨的发光光谱特性。顺式逆转为反式在与可见光以及特定波长的紫外线相互作用时也实现了异构化。在用强碱处理并同时对其吸收和发射光谱特性进行实质性调节的情况下，可以从配合物的二级配位域中除去两个苯并咪唑NH质子。有趣的是，在咪唑NH质子去质子化后，光异构化的速率常数以及量子产率急剧增加。还进行了使用密度泛函理论（DFT）和时变密度泛函理论（TD-DFT）的计算研究，以了解复杂主干中的电子电荷分布以及观察到的光谱带的适当分配。此外，