Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada.
J Am Chem Soc. 2010 Dec 8;132(48):17265-70. doi: 10.1021/ja107252f. Epub 2010 Nov 11.
The remarkable effect that secondary bonding interactions can have on the macroscopic properties of a material is illustrated by two polymorphs of the title compound. The phase which is most stable under ambient pressure and temperature consists of puckered supramolecular ribbon polymers assembled by Te--N secondary bonding interactions and displays a characteristic red-orange color. A second yellow phase consists of ribbons with alternating short and long intermolecular Te--N secondary bonding distances and is metastable; at 127 °C the material undergoes an exothermic irreversible transition to the red polymorph. A third phase consists of pyridine-solvated supramolecular dimers; it is also yellow and transforms into the red phase after the crystals effloresce. Computational DFT studies indicate that the observed changes in optical properties are related to intermolecular mixing of π orbitals enabled by the supramolecular interactions and the symmetry of the supramolecular synthon.
标题化合物的两种多晶型体说明了次级键相互作用对材料宏观性质的显著影响。在环境压力和温度下最稳定的相由 Te-N 次级键相互作用组装的褶皱超分子带状聚合物组成，并呈现出特征的橙红色。第二种黄色相由具有交替的短和长的分子间 Te-N 次级键距离的带状物组成，是亚稳的；在 127°C 时，材料经历放热的不可逆向红多晶型体的转变。第三种相由吡啶溶剂化的超分子二聚体组成；它也是黄色的，在晶体风化后转变为红相。计算 DFT 研究表明，观察到的光学性质变化与超分子相互作用和超分子合成子的对称性允许的π轨道分子间混合有关。
