Substituent Cross-Interaction Effects on the Electronic Character of the CN Bridging Group in Substituted Benzylidene Anilines − Models for Molecular Cores of Mesogenic Compounds. A <sup>13</sup>C NMR Study and Comparison with Theoretical Results
作者:Helmi Neuvonen、Kari Neuvonen、Ferenc Fülöp
DOI:10.1021/jo0600508
日期:2006.4.1
could be verified. The electroniceffects of the neighboring aromatic ring substituents systematically modify the sensitivity of the CN group to the electroniceffects of the benzylidene or aniline ring substituents. Electron-withdrawing substituents on the aniline ring decrease the sensitivity of δC(CN) to the substitution on the benzylidine ring, while electron-donating substituents have the opposite
在CDCl 3中,对一系列介晶分子模型化合物(即C 13)测量了13 C NMR化学位移δC (C N)。取代的亚苄基苯胺p -X C 6 H 4 CH NC 6 H 4 p -Y(X = NO 2,CN,CF 3,F,Cl,H,Me,MeO或NMe 2; Y = NO 2,CN ,F,Cl,H,Me,MeO或NMe 2)。δ的取代基依赖性Ç(CN)被用作研究电子取代基对偶氮甲碱单元的作用的工具。亚苄基取代基X有δ的反向效应Ç(C N):吸电子原因屏蔽的取代基,而给电子性的人的行为相反,感应效果清楚地在共振效应为主。相反,苯胺取代基Y发挥正常作用:吸电子取代基引起屏蔽,而供电子取代基引起C N碳屏蔽,感应效应和共振效应的强度非常相似。此外,可以验证X和Y之间是否存在特定的交叉相互作用。相邻芳环取代基的电子效应可系统地改变C的灵敏度N基团对亚苄基或苯胺环取代基的电子作用。吸电子苯胺环上的取代基降低δ的灵敏度Ç(C
Agracheva, E. B.; Krasnikova, L. Ya.; Gachkovskii, V. F., Journal of general chemistry of the USSR, 1980, vol. 50, p. 1870 - 1874
作者:Agracheva, E. B.、Krasnikova, L. Ya.、Gachkovskii, V. F.
DOI:——
日期:——
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作者:Alcaide, Benito、Mardomingo, Carmen L.、Plumet, Joaquin、Cativiela, Carlos、Mayoral, Jose A.
DOI:——
日期:——
Kroehnke, Chemische Berichte, 1938, vol. 71, p. 2583,2591
作者:Kroehnke
DOI:——
日期:——
Gawinecki, Ryszard; Muzalewski, Feliks, Polish Journal of Chemistry, 1984, vol. 58, # 10-12, p. 1091 - 1098