摘要
报道一系列取代苯基重氮盐及其18-冠醚-6络合物的远红外光谱、^(13)C核磁共振和FAB-质谱,由主体和客体形成络合物前后的光谱变化和这类络合物质谱中表征[M-BF_4]^+离子峰的相对丰度,结合取代基效应讨论络合物的成键状况,推测这类络合键除冠醚氧与重氮盐α-氮正电中心相互作用外,尚存在α-电子由重氮盐β-氮向冠醚氧转移的反馈作用。用Hückel分子轨道法对重氮盐各原子电荷密度分布计算的结果支持上述推论。
The Far-infrared ^(13)C NMR and FAB—MS of a series of substituted phenyldiazonium salts and their 18-crown-6 complexes are examined to discuss the bonding condition from the spectrum changes before and after complex formation, the relative abundance of [M-BF_4]^+ ion peak of these complexes in FAB-MS, and the substituent effects. It is inferred that there exists a back donation of π-electrons from the β-nitrogen atoms of diazonium salts to the oxegen atoms of crown ether besides the interaction between the oxegen atoms of crown ether and the positive charge in α-nitrogen of diazonium salts.
The distribution of electron density in diazonium salts is calculated by using Hücked molecular orbital method. The results support the above inference.
基金
国家自然科学基金
北京分子动态和稳态结构国家实验室资助
关键词
芳基重氮盐
冠醚
络合物
成键作用
arenediazonium salt, crown ether complex, far-IR, NMR, FAB-MS, complet bond
