Supramolecular kinetic effects by pillararenes: the synergism between spatiotemporal and preorganization concepts in decarboxylation reactions
作者:Eduardo Vieira Silveira、Rodrigo Montecinos、Leandro Scorsin、Luis Garcia-Rio、Michelle Medeiros、Vanessa Nascimento、Faruk Nome、Ricardo F. Affeldt、Gustavo A. Micke
DOI:10.1039/d1nj00551k
日期:——
to spontaneous hydrolysis of 6-NitroCBI relative to that of 5,6-DinitroCBI (ΔΔG‡ = 2.98 kcal mol−1) was determined experimentally, however similar transitions states were observed for both substrates. The host–guest complexes generated catalytic effects up to 7.1-fold on kobs, except for 6-NitroCBI⊂P5A which is the only system that presented unprecedent inhibitory kinetic effects. The data (kinetics
与3-阳离子-1,2-苯并恶唑(CBI)硝化衍生物(6-NitroCBI和5,6-DinitroCBI)的自发脱羧反应与两种阳离子柱芳烃(P5A和P6A)促进的超分子动力学相比,已进行了研究并为当前有关超分子和酶催化/抑制的理论的发展做出了贡献。较高的能量势垒,以6- NitroCBI相对的自发水解到5,6- DinitroCBI(ΔΔ ģ ‡ = 2.98千卡摩尔-1)中的溶液实验确定然而类似的过渡状态,观察到两个基板。主客体复合物对k obs的催化作用高达7.1倍,除了6-NitroCBI⊂P5A是唯一表现出前所未有的抑制动力学作用的系统。数据(动力学,1 H NMR滴定和分子动力学模拟)阐明了这四种配合物的几何形状,特别是通过修饰3个主要因素,揭示了这四种配合物的动力学效应:(1)溶剂和羧基之间的氢键数量的CBI,(2)异恶唑环的O–N键极化和(3)场效应降低NO 2基团的感应效应。