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在B3LYP/6-311++G(d)和ONIOM(B3LYP/6-311++g(d):PM3)水平上,研究了2-(2,5-二羟基苯基)-4(3H)-喹唑啉酮(DHPQ)及其在七元瓜环(CB7)限制下的双质子转移过程,确定了DHPQ分子各互变异构体的结构、能量以及基态质子转移反应的过渡态.通过对结构变化和能量差异的分析,探讨了DHPQ中的双质子转移机理,考察了质子转移的纳米笼效应以及该笼效应对质子转移热力学性质的影响,同时研究纳米腔与DHPQ的几何匹配关系以及水溶剂对包合物质子转移的影响.计算结果表明:DHPQ是采取分步转移机理,纳米腔的限制对质子转移过程产生一个很大的能垒,抑制分子内质子转移过程,水溶剂的引入促进Path 2,抑制Path 1.
The effect of 2- (2,5-dihydroxyphenyl) -4 (3H) -isomer on the level of B3LYP / 6-311 ++ G (d) and ONIOM (B3LYP / 6-311 ++ g (d) ) -quinazolinone (DHPQ) and its double proton transfer process under the restriction of seven-membered ring (CB7), the transition states of the structure, energy and ground state proton transfer reactions of the DHPQ molecule tautomers were determined. The mechanism of double proton transfer in DHPQ was discussed through the analysis of structural change and energy difference. The effect of proton transfer nanocage cage and the effect of cage effect on the thermodynamic properties of proton transfer were also investigated. Meanwhile, the geometrical matching between nanopore and DHPQ And the effect of water solvent on the proton transfer of the inclusion compound.The results show that DHPQ adopts a step-by-step transfer mechanism and the limitation of the nanocavity produces a great energy barrier to the proton transfer process, inhibiting the intramolecular proton transfer process, Introduced to promote Path 2, inhibit Path 1.