1H, 13C, and 19F NMR studies of phencyclone adducts of N-(polyhalophenyl)maleimides: evidence for dynamic NMR in maleamic acids
作者:Kimberly Marshall、Kerstin Rosmarion、Olga Sklyut、Nikolay Azar、Ronald Callahan、Robert Rothchild
DOI:10.1016/j.jfluchem.2004.07.002
日期:2004.12
anhydride with anhydrous ZnCl2 at ca. 200 °C. For the adducts (3), we observed slow exchange limit spectra on the 1H, 13C, [and 19F, for (3a–3c)] NMR timescales for the rotation of the unsubstituted bridgehead phenyls about the C(sp3)C(sp2) bonds, and for the rotations of the N-aryl rings about the N(sp2)C(aryl sp2) bonds. Ab initio calculations for geometry optimizations at the Hartree–Fock level with 6-31G*
NMR方法,包括1 H,13 C和19 F的一维和二维技术(在7.05 T),已被用于研究一些拥挤的苯环酮的Diels-Alder加合物的旋转受阻和磁各向异性(1)。在N-芳基环上带有多个卤素的对称取代的N-芳基马来酰亚胺(2)被用作亲二烯体以形成目标加合物(3)。马来酰亚胺包括:N-(4-溴-2,6-二氟苯基)马来酰亚胺(2a);和 N-(2,3,5,6-四氟苯基)马来酰亚胺(2b); ñ-(4-溴-2,3,5,6-四氟苯基)马来酰亚胺(2c); N-(2,3,4,5,6-五氯苯基)马来酰亚胺(2d); 和Ñ - (2,4,6-三溴苯基)马来酰亚胺(2E)。马来酰亚胺(2a - 2c)是由前体N-芳基马来酰胺酸(5a - 5c)制备的。这些马来酰胺酸在d 6-丙酮中的环境温度氟19 NMR显示出与中间交换速率过程相一致的明显的异常峰展宽,这可能与N-芳基旋转过程相对应。马来酰亚胺(2d)和(2e一步法分别由五氯苯胺或2