BACKGROUND Donor acceptor moieties connected through π-conjugated bridges i.e. D-π-A, in order to facilitate the electron/charge transfer phenomenon, have wide range of applications. Many classes of organic compounds, such as cyanine, coumarin carbazole, indoline, perylene, phenothiazine, triphenylamine, tetrahydroquinoline and pyrrole can act as charge transfer materials. Phenothiazines have been extensively studied as electron donor candidates due to their potential applications as electrochemical, photovoltaic, photo-physical and DSSC materials. RESULTS Two phenothiazine derivatives, 2-((10-hexyl-10H-phenothiazin-3-yl)methylene)malononitrile (3a) and 2-((10-octyl-10H-phenothiazin-3-yl)methylene)malononitrile (3b) have been synthesized in good yields and characterized by various spectroscopic techniques like FT-IR, UV-vis, (1)H-NMR, (13)C-NMR, and finally confirmed by single crystal X-ray diffraction studies. Density functional theory (DFT) calculations have been performed to compare the theoretical results with the experimental and to probe structural properties. In order to investigate the excited state stabilities the absorption studies have been carried out experimentally as well as theoretically. CONCLUSIONS Compound 3a crystallises as monoclinic, P2 (1)/a and 3b as P-1. The X-ray crystal structures reveal that asymmetric unit contains one independent molecule in 3a, whereas 3b exhibits a very interesting behavior in having a higher Z value of 8 and four independent molecules in its asymmetric unit. The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the molecules indicates the potential sites for chemical reactivities. Furthermore, high first hyperpolarizability values entitle these compounds as potential candidates in photonic applications.Graphical abstractPhenothiazines; a comparison of experimental and theoretical analysis.

中文翻译：

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2-（（10-烷基-10H-吩噻嗪-3-基）亚甲基）丙二腈衍生物的合成和结构性能; 结合了实验和理论上的见识。

背景技术通过π共轭桥即D-π-A连接的供体受体部分，为了促进电子/电荷转移现象，具有广泛的应用范围。花青，香豆素咔唑，二氢吲哚，per，吩噻嗪，三苯胺，四氢喹啉和吡咯等多种有机化合物可以用作电荷转移材料。吩噻嗪由于其在电化学，光伏，光物理和DSSC材料中的潜在应用而被广泛研究为电子供体候选物。结果两种吩噻嗪衍生物2-（（10-hexyl-10H-吩噻嗪-3-基）亚甲基）丙二腈（3a）和2-（（10-辛基-10H-吩噻嗪-3-基）亚甲基）丙二腈（3b）已合成且收率高，并已通过多种光谱技术进行了表征，例如FT-IR，UV-vis，（1）H-NMR，（13）C-NMR，并最终通过单晶X射线衍射研究得到证实。进行了密度泛函理论（DFT）计算，以将理论结果与实验结果进行比较，并探讨结构特性。为了研究激发态的稳定性，已经在实验和理论上进行了吸收研究。结论化合物3a结晶为单斜晶，P2（1）/ a和3b结晶为P-1。X射线晶体结构表明，不对称单元在3a中包含一个独立分子，而3b在其不对称单元中具有较高的Z值为8和四个独立分子时表现出非常有趣的行为。映射在分子整个稳定几何结构上的分子静电势（MEP）表示化学反应性的潜在位点。此外，高的第一超极化率值使这些化合物成为光子应用中的潜在候选物。实验和理论分析的比较。