The development of new hybrid photochromic materials (HPMs) systems received huge interest of chemists because of their potentialities in many domains and feasibilities of obtaining other photomodulated chemo-physical properties. The photoinduced electron transfer (ET) based on electron-donor (ED) and electron-acceptor (EA) species, together with a crystal engineering strategy, has been efficient in fabricating crystalline HPMs (CHPMs) with a tunable photoresponsive functionality. Compared with the previously investigated polypyridines as EAs, in this work, the introduction of polyimidazoles, tris(4-(1H-imidazol-1-yl)phenyl)amine (TIPA) as potential EAs, into a zinc-halogen ion (X– = Cl–, Br–, I–)-phosphite system produces three hybrid phosphites, [Zn2Cl2(HPO3)(TIPA)] (1), [Zn2Br2(HPO3)(TIPA)]·2H2O (2), and [Zn4I2(HPO3)2(HCO2)2(TIPA)2]·3H2O (3). In isostructural 1 and 2, the TIPA bridges neutral tetramers [Zn4(μ3-HPO3)2X4] to form a layered structure. Complex 3 features similar building units of [Zn4(μ3-HPO3)2I2(HCOO)2], which could be viewed as the partial substitution of terminal ligands X– of [Zn4(μ3-HPO3)2X4] with formate (HCOO–). In 3, the TIPA connects tetranuclear units to yield the resulting layered skeleton. As anticipated, 1–3 exhibit photochromism driven by the ET from tetranuclear species as EDs to TIPA as EAs. Although 1–3 have an isotopological architecture with the same linkers as EAs and similar building units as EDs, they exhibit distinct photochromic performances. Their photochromic performances could be modulated by the coordination microenvironment of metal ions of the tetranuclear units. Our work provides a facile method to tune the photochromic functionality of the resulting complexes via modulating the coordination microenvironment of metal ions or building units.
新型混合光变材料(HPMs)系统的发展受到了
化学家的广泛关注,因为它们在许多领域的潜力和获得其他光调制
化学物理性质的可行性。基于电子供体(ED)和电子受体(EA)物种的光诱导电子转移(ET),结合晶体工程策略,在制造具有可调光响应功能的晶体HPMs(CHPMs)方面取得了显著成效。与之前研究过的聚
吡啶作为电子受体相比,本研究将聚
咪唑和三(4-(
1H-咪唑-1-基)苯基)胺(TIPA)作为潜在电子受体引入
锌卤离子(X– = Cl–, Br–, I–)-
磷酸盐体系,生成三种混合
磷酸盐,[Zn2Cl2(HPO3)(TIPA)](1)、[Zn2Br2(HPO3)(TIPA)]·2H2O(2)和[Zn4I2(HPO3)2(HCO2)2(TIPA)2]·3H2O(3)。在同构的1和2中,TIPA桥接中性四聚体[Zn4(μ3-HPO3)2X4]形成层状结构。复合物3具有类似的构建单元[Zn4(μ3-HPO3)2I2(HCOO)2],可以看作是将[Zn4(μ3-HPO3)2X4]的末端
配体X–部分替换为
甲酸根(HCOO–)。在3中,TIPA连接四核单元,形成最终的层状骨架。如预期的那样,1–3表现出由四核物种作为电子供体向TIPA作为电子受体的驱动光变性。尽管1–3有着相同的电子受体
配体的同类构架和相似的电子供体的构建单元,但它们表现出不同的光变性能。它们的光变性能可以通过四核单元
金属离子的配位微环境进行调节。我们的研究提供了一种简单的方法,通过调节
金属离子的配位微环境或构建单元来调节所得复合物的光变功能。