Nitrogen NMR study of some mesoionic oxadiazoles and thiadiazoles
Nitrogen NMR study of some mesoionic oxadiazoles and thiadiazoles
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一些介离子恶二唑和噻二唑的氮核磁共振研究
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
G. Webb
中科院分区：
文献类型：
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作者：
J. Jaźwiński;O. Staszewska;J. Wiench;L. Stefaníak;S. Araki;G. Webb
报道了10种中离子恶二唑和噻二唑的~（15）N化学位移。一些支持的14 N和13 C NMR数据也被报道，以及一些从头计算分子轨道计算和X射线衍射数据。讨论了化合物结构与~（15）N化学位移的关系。14 N NMR测量和从头计算分子轨道计算，以确定所研究的分子内的电荷分布。给出了中离子型恶二唑、噻二唑和乙酰基缩酮亚胺的1 J（C_4，C_5），2 J（15 N，13 C）和1 J（15 N，13 C）自旋偶合数据.报道了乙酰基悉尼酮亚胺和3，1，2，-噻二唑的苦味酸盐的X射线衍射数据。中离子骨架内的键长介于单键和双键的值之间，表明为共轭键系统。在固态中观察到的acetylosydnonimine的环外基团的安排对应于通过溶液NMR研究预测的安排。版权所有© 2000约翰威利父子有限公司。
15N chemical shifts are reported for 10 mesoionic oxadiazoles and thiadiazoles. Some supporting 14N and 13C NMR data are also reported, together with some ab initio molecular orbital calculations and x‐ray diffraction data. The relation between compound structure and 15N chemical shifts is discussed. 14N NMR measurements and ab initio molecular orbital calculations are employed to identify the charge distributions within the molecules studied. Some 1J(C4,C5), 2J(15N,13C) and 1J(15N,13C) spin coupling data for mesoionic oxadiazoles, thiadiazoles and acetylosydnonimines are given. X‐ray diffraction data for the picrate of acetylsydnonimine and a 3,1,2,‐thiadiazole are reported. The bond lengths within the mesoionic backbone are intermediate between the values for single and double bonds, suggesting a conjugated bond system. The arrangement of the exocyclic group observed in the solid state for acetylosydnonimine corresponds to the arrangement predicted by solution NMR studies. Copyright © 2000 John Wiley & Sons, Ltd.