Ureidobenzotriazine Multiple H-Bonding Arrays: The Importance of Geometrical Details on the Stability of H-Bonds
作者:G. B. W. L. Ligthart、Dawei Guo、A. L. Spek、Huub Kooijman、Han Zuilhof、Rint P. Sijbesma
DOI:10.1021/jo7019338
日期:2008.1.1
functional calculations of conformations 1a and 1b together with two complexes revealed the clearly nonplanar geometry of the multiply hydrogen-bonded complex, in which some bonds are significantly longer (3.2 Å) than is optimal for H-bonds. As a result, only very small free energies of association were calculated, in line with the experimentally observed absence of specific assembly of the components
成功合成了3-ureidobenzo-1,2,4-triazine 1- N-氧化物(1)。该衍生物在CDCl 3和DMSO- d 6溶液中以及在固态下均显示一个受体-供体-受体-受体(ADAA)氢键基序。尽管在DAD图案中观察到了1的中等强度结合,但是在具有互补DADD阵列的脲基吡啶中却观察到了非特异性结合。构型1a和1b的密度泛函计算连同两个配合物一起揭示了多重氢键配合物的明显非平面几何形状,其中一些键的长度(H 2键)明显长于最佳(3.2Å)。结果,根据实验观察到的组分的特定组装的缺乏,仅计算了非常小的缔合自由能。