N-取代硼氮丁烷类似物的合成、结构和性质研究

发布时间：2018-04-29 06:19

本文选题：N-取代硼氮丁烷类似物 + 氨基乙硼烷　；参考：《河南师范大学》2017年硕士论文

【摘要】：N-取代硼氮丁烷类似物作为胺硼烷储氢材料的关键中间产物而受到大家的广泛关注。环硼氮烷和胺硼烷化合物是其脱氢产物,可作为低压合成氮化硼的前驱体,因此N-取代硼氮丁烷类似物也是合成氮化硼的潜在前驱体。已经报道的少数N-取代硼氮丁烷类似物的制备需要在低温条件下进行,反应时间长,提纯过程复杂,进而限制了对该类化合物性质及应用方面的研究,仅有初步对硼氮丁烷类似物热分解和金属催化重排机理的研究。故系统研究N-取代硼氮丁烷类似物的合成和性质,对于丰富硼氮丁烷类似物和挖掘其潜在的应用具有重要的意义。本论文利用19种胺与氨基乙硼烷发生亲核反应,合成了一系列N-取代硼氮丁烷类似物,采用核磁、红外、单晶衍射、XRD等测试手段对产物进行表征,并系统研究N-取代硼氮丁烷类似物的稳定性和热分解性质。研究结果表明:1)氨基乙硼烷与胺反应可以在室温下进行,且反应迅速。氨基乙硼烷与胺的反应,可能取决于氮原子上取代基的大小和个数。2)N-取代硼氮丁烷类似物BH_2中B的化学位移相对NH_3BH_2NH_2BH_3向低场移动,而BH_3中B的化学位移无明显变化。通过DFT理论计算发现端基和中间硼原子上自然电荷的变化与实际化学位移变化趋势一致。N-取代硼氮丁烷类似物B1H中H的化学位移相对NH_3BH_2NH_2BH_3向高场移动,N1H中H的化学位移向低场移动,可能是由于端基氮原子上的氢被取代基取代引起的。3)N-取代硼氮丁烷类似物存在全反式和半反式两种构型及分子内双氢键和分子间双氢键。多数该类化合物两端的硼氮键键长相差不多,但均比中间硼氮键长要大。4)端基氮是一级、二级、三级胺的N-取代硼氮丁烷类似物稳定性依次减小;由于双氢键的作用,N-取代硼氮丁烷类似物的熔点与相应烷烃等电子体化合物相比较高;通过对N-取代硼氮丁烷类似物在不同溶剂中热分解产物分析,推测N-取代硼氮丁烷类似物在THF和CH_2Cl2中分解机理不同,但均形成氨基乙硼烷中间体,在THF中氨基乙硼烷进一步转化形成H_3N·BH_3,R3N·BH_3,[NHBH]3和[NH_2BH_2]x,在CH_2Cl2中氨基乙硼烷进一步转化形成R3N·BH_3,[NHBH]3和[NH_2BH_2]_x。
[Abstract]:N- substituted boronazobutane analogues as the key intermediate products of amine borane hydrogen storage materials have attracted wide attention. Cycloboronazane and amine borane compounds are the dehydrogenation products of boron nitride and can be used as precursors for the synthesis of boron nitride at low pressure, so N- substituted boron nitrogen butane analogues are also potential precursors for the synthesis of boron nitride. The preparation of a few N- substituted boron butane analogues has been reported to be carried out at low temperature, the reaction time is long and the purification process is complex, which limits the study on the properties and applications of these compounds. Only the mechanism of thermal decomposition and metal catalytic rearrangement of boron nitrogen butane analogue was studied. Therefore, it is of great significance to study the synthesis and properties of N-substituted borobutane analogues in order to enrich boron nitrogen butane analogues and exploit their potential applications. In this paper, a series of N-substituted borobutane analogues were synthesized by the nucleophilic reaction of 19 amines with aminoethylborane. The products were characterized by NMR, IR and XRD. The stability and thermal decomposition of N-substituted boron butane analogue were studied. The results show that the reaction of amino ethylborane with amine can be carried out at room temperature, and the reaction is rapid. The reaction of aminoethylborane with amine may depend on the size and number of substituents on nitrogen atoms. The chemical shift of B in BH_2, a boron N-butane analogue, moves to a lower field than that of NH_3BH_2NH_2BH_3, but the chemical shift of B in BH_3 has no obvious change. It is found by DFT theory that the change of natural charge on the terminal group and intermediate boron atom is consistent with the change trend of actual chemical shift. The chemical shift of H in B1H, a boronazobutane analogue, moves to a higher field with respect to NH_3BH_2NH_2BH_3. The displacement moves to the lower field, It may be due to the substitution of hydrogen on the terminal nitrogen atom that the analogue of boron N-butane has two configurations: all-trans and semi-trans, intramolecular double hydrogen bond and intermolecular double hydrogen bond. Most of these compounds have the same appearance of boron and nitrogen bond at both ends, but the length of boron and nitrogen bond is larger than that of intermediate boron nitrogen bond, and the stability of N-substituted N-butane analogue of second-order amine decreases in turn. The melting point of N-substituted boronazobutane analogues is higher than that of corresponding electron compounds such as alkanes because of the effect of dihydrogen bonds. The thermal decomposition products of N-substituted boronazobutane analogues in different solvents are analyzed. It is inferred that N-substituted boronazobutane analogues have different decomposition mechanisms in THF and CH_2Cl2, but they all form aminoethylborane intermediates. In THF, aminoethylborane is further transformed into H3N BH3N BH3, [NHBH] 3 and [NH_2BH_2] x in THF. In CH_2Cl2, aminoethylborane is further converted to R3N BH3, [NHBH] 3 and [NH_2BH_2] x.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34

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