氨基乙硼烷的反应及反应机理研究

Aminodiborane is one of the oldest boron-nitrogen compound, but owing to the difficulties in synthesis, little work has been done to investigate the structure, characteristics and application of aminodiborane over the past seventies years. Recently, new facile method has been published to prepare aminodiborane at room temperature, which make it possible to investigate the characteristics and application of aminodiborane systematically. As a derivative from diborane in which one of the two bridge hydrogens has been replaced by an amino group, aminodiborane is active four ring amine-borane compound. In this proposed project, reactivity and mechanism of aminodiborane will be investigated. Fistly, the reactions between aminodiborane and Lewis acid/base will be studied systematically. Typical Lewis acid including acid, alcohol, phenolic compound and Lewis base including amine, sulfide, phosphine, alkali- and alkaline earth metals and its hydride/amino compound, alkene and alkyne will be chosen to react with aminodiborane, and the key factors which influencing the product and mechanisms will also be studied. Then the reaction mechanism and dynamics will also be investigated systematically by means of experiment and theoretical calculations. Several experiment strategies will be used to studied the mechanisms including tracing the reaction process, captureing or detecting the intermediate, isotope labeling and reaction kinetics.

氨基乙硼烷早在1938年就被发现，但70多年来该化合物并未得到充分研究，主要受制于早期苛刻的合成条件。最近报道的简易制备氨基乙硼烷的新方法使得系统研究该化合物成为可能。作为乙硼烷分子中一个桥氢被氨基取代的衍生物，氨基乙硼烷有不稳定的四元环结构，预期反应活性较高。本项目主要研究氨基乙硼烷的反应及反应机理：1. 氨基乙硼烷与路易斯酸、路易斯碱的反应研究：系统研究路易斯酸（强酸、醇、酚）及路易斯碱（含孤对电子的氮/硫/磷化合物、s区活泼金属及其氢化物/胺基化合物、含π电子的化合物）与氨基乙硼烷的反应，探讨实验条件对反应及产物的影响，跟踪反应过程，对产物进行结构表征和性质测试。2.氨基乙硼烷与路易斯酸、路易斯碱的反应机理研究：在实验过程的跟踪、反应中间体的捕捉或检测、同位素标记及反应动力学研究的基础上，结合理论计算分析研究氨基乙硼烷与路易斯酸、路易斯碱的反应机理。

近年来，硼氮氢化合物因其在储氢材料、还原剂及制备其他新型硼氮材料方面的应用而受到广泛关注。作为乙硼烷分子中一个桥氢被氨基取代的衍生物，氨基乙硼烷有不稳定的四元环结构，反应活性较高。本项目主要研究了氨基乙硼烷及其衍生物的反应及反应机理：1. 氨基乙硼烷及其衍生物与路易斯酸和路易斯碱均能发生反应，反应物、溶剂、温度等对反应过程及产物均有不同程度的影响，利用该类反应合成了一系列新的硼氮氢化合物，并对其结构、性质等进行表征。2.结合实验和理论计算，发现氨基乙硼烷及其衍生物中硼原子的缺电子特性及与硼相连的负电性氢原子在反应过程中起着重要作用，氨基乙硼烷与胺的反应是通过氮原子上的孤对电子亲核进攻ADB中缺电子的硼，可自发发生快速的亲核反应。而与硼相连的负电性氢与质子酸中的正电性氢形成的双氢键作用在氨硼烷和胺基乙硼氢负离子与路易斯酸的反应过程中发挥着重要作用，而非硼先与富电子的酸根作用后再通过协同作用形成双氢键，进而引发释氢反应。该系列基础研究对设计合成新的硼氮氢化合物、发展硼氮氢化学及解决能源问题具有重要意义。