An experimental and theoretical study of dinitrogen related chemistry: Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions.

摘要

eamination reactions play an important role in synthetic organic chemistry and their pathways often involve highly unstable, reactive aliphatic diazonium ions. It is the goal to utilize the power of modern ab initio theory coupled to laboratory experimentation to gain a better understanding of the electronic structures of these reactive intermediates. The first crystal structures of aliphatic diazonium ions, ;Potential conjugative interactions are pivotal to discussions of the stereochemistry and of the electronic structure of para-substituted acetophenone azines. With a series of symmetric para-substituted acetophenone azines, the stereochemistry and the electronic structures are investigated experimentally and theoretically. Unlike the case of parent system, formaldazine, which prefers N-N s-trans conformation, all the results indicate that the symmetric para-substituted acetophenone azines assume N-N gauche conformations and the phenyl rings are twisted out the best plane without indication of conjugation in the solid state, in solution, and in the gas phase.;Furthermore, the structural analyses demonstrate that there are no significant manifestations of N-N conformation and of phenyl conjugation effects even with push and pull substituents on the asymmetric para-substituted acetophenone azines. The Natural Population Analysis (NPA) shows that there is no charge transfer in the asymmetric azines. Asymmetrical azines with acceptor and donor groups in the para positions on opposing ends of the molecule can be excellent candidates of novel nonlinear optical (NLO) materials. Some azines have the values of the first hyperpolarizability,