Branched non-covalent complexes between carboxylic acids and two tris(amidines)
作者:Arno Kraft
DOI:10.1039/a809190k
日期:——
Carboxylic acids and two tris(amidine) bases formed branched 3∶1 complexes with high solubility in chlorinated and aromatic solvents, particularly when aromatic carboxylic acids with suitable solubilising substituents were used. Whereas N,N′-diethylamidine complexes 10 proved to be difficult to isolate, the respective imidazoline complexes 14 were easily purified by crystallisation. Association constants were determined for model bis(imidazoline) complexes to be about 103 dm3 mol–1 in the competitive solvent mixture CDCl3–CD3OD (97∶3).
Hydrogen-bonding between benzoic acid and an N,N′-diethyl-substituted benzamidine
作者:Arno Kraft、Lars Peters、Harold R Powell
DOI:10.1016/s0040-4020(02)00301-0
日期:2002.4
structure of 4,N,N′-triethylbenzamidinium benzoate is reported in which the benzoate anion and the (E,E)-configured amidinium group are linked through two hydrogen bonds (with an N⋯O distance of 2.723 Å). Since an amidine (E,E) isomer was also observed for chloroform solutions of the complex, the binding mode in the crystal and in solution was analogous to that reported for unsubstituted amidines. The strong
据报道4,N,N'-三乙基苯甲mid基苯甲酸铵的合成和晶体结构,其中苯甲酸根阴离子和(E,E)am基通过两个氢键连接(N = O距离为2.723Å) 。由于在配合物的氯仿溶液中也观察到an(E,E)异构体,因此晶体和溶液中的结合模式类似于未取代am的报道模式。从电位滴定中可以明显看出N,N'-二乙基取代的苯甲am的强碱性(p K a在水-二恶烷中为11.99±0.02,1:1)。