Chen Ze, Xue Yuncong, Gui Mingliang, Wang Cong, Wang Feng
CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
Inorg Chem. 2020 May 4;59(9):6481-6488. doi: 10.1021/acs.inorgchem.0c00575. Epub 2020 Apr 10.
The self-assembly of π-aromatic organic and organometallic molecules into long-range-ordered supramolecular polymers is dictated by a variety of molecular parameters and external conditions. In this work, structural isomerism, representing one of the potent molecular parameters, has been investigated to modulate the self-assembly behaviors. Two platinum(II) acetylide-based structural isomers, with different -hexyl substitution positions on the inner benzotriazole core, have been designed. Thanks to the synergistic participation of hydrogen-bonding and π-π-stacking interactions, both platinum(II) acetylide-based compounds are prone to forming supramolecular polymers via a nucleation-elongation cooperative mechanism in apolar media. Thermal hysteresis phenomena are observed for both compounds, suggesting the different supramolecular polymerization pathways upon cooling and heating. Remarkably, in addition to the spectroscopic difference, these two supramolecular polymers display distinct thermostability and rheological moduli, ascribing to different binding enthalpies of the neighboring monomers. Overall, it is evident that a minor variation at the molecular level brings huge differences to the properties of long-range-ordered supramolecular polymers. The current study illustrates the importance of the structural isomerism effect for the rational design of π-functional supramolecular materials.
π-芳香族有机和有机金属分子自组装成长程有序的超分子聚合物，受多种分子参数和外部条件的支配。在这项工作中，作为重要分子参数之一的结构异构现象，已被研究用于调控自组装行为。设计了两种基于乙炔铂(II)的结构异构体，它们在内部苯并三唑核上的己基取代位置不同。由于氢键和π-π堆积相互作用的协同参与，两种基于乙炔铂(II)的化合物在非极性介质中都易于通过成核-伸长协同机制形成超分子聚合物。两种化合物均观察到热滞后现象，这表明冷却和加热时超分子聚合途径不同。值得注意的是，除了光谱差异外，这两种超分子聚合物还表现出不同的热稳定性和流变模量，这归因于相邻单体的结合焓不同。总体而言，很明显分子水平上的微小变化会给长程有序超分子聚合物的性质带来巨大差异。当前的研究说明了结构异构效应对于合理设计π-功能超分子材料的重要性。
