Two polymorphs and cocrystal of styryl-pyridine derivatives with tuned emission induced by Co2+ and Zn(phen)32+
作者:Ruilong Zhang、Qiong Zhang、Zhaodi Liu、Longmei Yang、Jieying Wu、Hongping Zhou、Jiaxiang Yang、Yupeng Tian
DOI:10.1039/c3ce42069h
日期:——
A styryl-pyridine derivative, 2,5-dibutoxy-1,4-bis[2-(4-pyridyl)ethenyl]benzene (L), has been designed and synthesised. Two polymorphs of L and crystals of [Zn(phen)3]2L(ClO4)4 were obtained by different crystallisation conditions. Polymorph-α was prepared by a solvent evaporation method. However, polymorph-β and a cocrystal of [Zn(phen)3]2L(ClO4)4 were obtained by different inducing reagents. It has been found that there are, in total, four independent conformations of the molecule L in the three kinds of crystals. We have calculated the standard molar enthalpy of formation (ΔHm) of each conformation and demonstrated that the stabilisation energy of each conformation significantly relies on both the planarity of the molecules (L) and bond length of conjugated bridges. Furthermore, the photophysical properties of the three kinds of crystals also exhibit differences in the vibration and absorption spectroscopies, solid-state photoluminescence and time-resolved fluorescence, which may arise from the chromophore's stacking modes and the intermolecular electronic interactions in the crystals. These results revealed that the optical properties of functional organic materials could be tuned by controlling their crystallisation environment for a specific molecule.
设计并合成了一种芪基吡啶衍生物2,5-二丁氧基-1,4-双[2-(4-吡啶基)乙烯基]苯(L)。通过不同的结晶条件获得了L的两种多晶型物及[Zn(phen)3]2L(ClO4)4的晶体。多晶型物α采用溶剂挥发法制备,而多晶型物β和[Zn(phen)3]2L(ClO4)4共晶则是通过不同的诱导剂获得。在三种晶体中,分子L总共有四种独立的构象。我们计算了每种构象的标准摩尔生成焓ΔHm,并证明每种构象的稳定化能显著依赖于分子L的平面性和共轭桥的键长。此外,三种晶体的光物理性质在振动和吸收光谱、固体荧光和时间分辨荧光方面也表现出差异,这可能源于发色团的堆积模式和晶体中分子间的电子相互作用。这些结果揭示了功能性有机材料的光学性能可以通过控制特定分子的结晶环境来进行调节。