Transition structures and energy barriers of the concerted prototypical cycloaddition reaction of 1,3-heterocumulenes (S=C=S, S=C=NR, RN=C=NR, and heteroanalogs) to acetylene resulting in nucleophilic carbenes were calculated by G2(MP2) and CBS-Q ab initio quantum chemical and by density functional theory (DFT) methods. According to the calculations the activation energies (activation enthalpies) of
用G2计算1,3-杂枯烯(S = C = S,S = C = NR,RN = C = NR和杂类似物)生成乙炔的亲核碳烯的原型原型协同加成反应的过渡结构和能垒。 MP2)和CBS-Q从头算量子化学,并采用密度泛函理论(DFT)方法。根据这些计算,同质异原子的枯草晶的活化能(活化焓)以O> S> Se和NH> PH的顺序降低,而反应能以O> S的顺序约Se和PH> NH的顺序降低。尽管第一反应比第二反应的放热少,但是二硫化碳和乙炔的反应比碳二亚胺和乙炔的反应具有更低的反应势垒。1的循环稳定性更强 根据变形和稳定能以及键指数来讨论过渡态的3-二硫醇-2-亚烷基。通过DFT和DFT:PM3两层混合ONIOM方法检查了二硫化碳与环应变环庚炔的已知反应。与定性实验结果一致,如果CH(2)在3,3,7,7-四甲基的5位上,则活化能增加,反应能量减少,顺序为S,SO(2)和SiMe(2) -1-环庚炔分