DAST晶体（即4-N, N-二甲胺基-4’-N’-甲基-氮杂芪的对甲苯磺酸盐晶体）具有优良的二阶非线性光学性能和电光效应特性，可用于红外至太赫兹波段辐射与检测领域。为了表征DAST源粉分子结构及纯度，选择CD3OD和DMSO-d6两种溶剂分别对DAST源粉进行了1H NMR、13C NMR、1H-1H COSY、HSQC和HMBC表征。通过对谱峰的归属及分析发现，DAST在CD3OD溶液中倾向于以离子对状态存在，而在DMSO-d6溶液中倾向于以解离状态存在，并根据谱峰的变化推测了DAST在从CD3OD溶液环境向DMSO-d6溶液环境变化时解离过程中电子云在共轭结构上重新分布的规律和骨架的变化情况。%DAST crystal (4-N,N-dimethylamino-4’-N’-methyl-stilbazolium tosylate crystal) shows electro-optical effect, and has excellent properties for second-order nonlinear optics. It can be used for wave radiation and detection from infrared to terahertz range. In this study, the molecular structure and purity of DAST crystal were analyzed by liquid-state NMR spectroscopy (i.e.,1H NMR,13C NMR,1H-1H COSY, HSQC and HMBC) using CD3OD and DMSO-d6 as solvents. It was observed that DAST tended to exist in the form of ion pair in CD3OD solution, while in the form of dissociative state in DMSO-d6solution. This could be due to solvent-dependent redistribution of electron cloud in the conjugated structure and movement of the framework.
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