Structure and protonation study of the imidazo[2,1-b]-1,3,4-thiadiazole system: 1H nuclear magnetic resonance, crystal and molecular structure of 5,6-dimethylimidazo[2,1-b]-1,3,4-thiadiazole and its hydrobromide
作者:Maria Luisa Schenetti、Ferdinando Taddei、Lucedio Greci、Leonardo Marchetti、Gianni Milani、Giovanni Dario Andreetti、Gabriele Bocelli、Paolo Sgarabotto
DOI:10.1039/p29800000421
日期:——
Crystal structure analysis of 5,6-dimethylimidazo[2,1-b]-1,3,4-thiadiazole (3) and its corresponding hydrobromide has shown that protonation occurs at N(7). Molecular properties, mainly aromaticity and basicity, of this system were interpreted on the basis of semi-empirically calculated ring-currents, which show that this molecule has a lower aromatic character than that of other fused heterocycles
5,6-二甲基咪唑并[2,1- b ] -1,3,4-噻二唑(3)及其对应的氢溴酸盐的晶体结构分析表明,质子化发生在N(7)。基于半经验计算的环电流解释了该系统的分子特性,主要是芳香性和碱性,这表明该分子的芳香性低于咪唑与嘧啶和噻唑环的其他稠合杂环。从1 H nmr测量无法确定酸性溶液中的质子化位点,但发现N(7)是可在镧系元素转移试剂存在下形成复合物的位点。