3,3'-偶氮双(6-氨基-1,2,4,5-四嗪)新法合成、表征与量子化学研究

Novel Synthesis,Characterization and Quantum Chemistry Study on 3,3'-Azobis(6-amino-1,2,4,5-tetrazine)

自行设计了3,3'-偶氮双(6-氨基-1,2,4,5-四嗪)(DAAT)新合成路线、采用3,5-双(3,5-二甲基吡唑-1-基)-1,2,4,5-四嗪(BDT)为原料,由文献报道的4步反应缩减为2步,经高压氨解、高锰酸钾氧化合成了DAAT,总收率大幅提高,达到58.1%,并采用元素分析、红外光谱、核磁共振光谱等进行了结构表征.为了从分子水平探索DAAT的性能,采用B3LYP法,在6-31G(d,p)基组水平上对DAAT的结构进行了优化,计算了其性能,获得稳定的几何构型、分子轨道及键级;在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质,并得温度对热力学性能影响的关系式.结果表明:DAAT分子结构中偶氮基两侧的四嗪环和氨基基本在同一个平面上,形成一个大的共轭π键;红外谱计算频率和强度与实验结果整体吻合较好;热能(Et,m)、热容(Cp,m)和熵(Sm)均随温度的升高而增大.

A novel synthetic approach of 3,3＇-azobis（6-amino-1,2,4,5-tetrazine） （DAAT） was firstly devised. Taking 3,6-bis（3,5-dimethylpyrazol-1-yl）-1,2,4,5-tetrazine （BDT） as a primary material, DAAT was synthesized by highpressure ammonolysis and potassium permanganate oxidation. Compared with the four-step reaction in the literature, this new approach was reduced to two steps with a yield of 58.1%. The intermediate and DAAT were characterized by elemental analysis, IR and NMR spectra. In order to investigate properties of DAAT at a molecular level, the structure of DAAT was optimized and its properties were calculated by a B3LYP method on 6-31G（d,p） basis set. The steady geometric configuration and bond order were obtained. The vibrational frequencies, IR spectra and thermodynamics properties at different temperatures were obtained on the basis of vibrational analysis, and the relationship between tem- perature and thermodynamics properties was deduced. The conclusion was drawn that the tetrazine ring and amino group in the DAAT structure were in a plane and were able to build a conjugated n-bond, the calcu- lated frequency and intensity were consistent with the experimental values in IR spectra, all thermal energy （ Et,m ）, thermal capacity （ Cp,m ） and entropy （Sm ） would increase with the increase of temperature.