NMR and quantum chemical studies on association of 2,6-bis(acylamino)pyridines with selected imides and 2,2′-dipyridylamine
作者:Borys Ośmiałowski、Erkki Kolehmainen、Ryszard Gawinecki、Reijo Kauppinen、Juha Koivukorpi、Arto Valkonen
DOI:10.1007/s11224-010-9646-2
日期:2010.10
Association constants of 2,6-bis(alkylcarbonylamino)pyridines (alkyl = methyl or ethyl) and their perfluoroalkyl analogues with succin- and maleimide as well as with 2,2′-dipyridylamine (complementary DAD and ADA hydrogen bonding motifs are responsible for formation of the associates) have been determined by NMR titrations and quantum chemical calculations. Interactions of 2,6-bis(alkylcarbonylamino)pyridines with imides differ by character from these of perfluoroalkyl analogues. Such large difference was not observed for the 2,2′-dipyridylamine associates. Since fluorine atoms cause carbonylamino groups to be stronger hydrogen bond donors, perfluorinated species of this type were found to be more stable. Single crystal X-ray structures of 2,6-bis(trifluoromethylcarbonylamino)pyridine and 2,6-bis(pentafluoroethylcarbonylamino)pyridine have been also determined.
通过核磁共振滴定和量子化学计算,确定了2,6-双(烷基羰基氨基)吡啶(烷基 = 甲基或乙基)及其全氟烷基类似物与琥珀酰亚胺和马来酰亚胺以及2,2′-二吡啶胺(互补的DAD和ADA氢键图案负责形成关联)的关联常数。2,6-双(烷基羰基氨基)吡啶与亚胺的相互作用与全氟烷基类似物的相互作用不同。2,2′-二吡啶胺关联没有观察到这种大的差异。由于氟原子使羰基氨基成为更强的氢键供体,因此发现这种全氟化物质更稳定。还确定了2,6-双(三氟甲基羰基氨基)吡啶和2,6-双(五氟乙基羰基氨基)吡啶的单晶X射线结构。