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合成了新型的1,3-二(1-二茂铁磺酰基-2-苯并咪唑)丙烷(BFBP).用红外光谱、核磁、质谱和X射线单晶衍射对其结构进行了表征.该晶体结构属正交晶系,空间群为Pnma,晶胞参数为:a=1.30079(13)nm,b=2.9627(3)nm,c=1.01257(10)nm,V=3.9023(7)nm3,Dc=1.492 g/cm3,μ=0.907 mm-1,F(000)=1816,Z=4,R1=0.0506,wR2=0.1583.晶体结构表明,标题化合物的两个二茂铁磺酰基采取顺式连接方式,即为顺式构象而不是反式构象.运用密度泛函理论,采用B3LYP/6-31G方法,分别对标题化合物的顺式和反式构象进行几何全优化,得到两种优化结构α-BFBP(顺式优化结果)和β-BFBP(反式优化结果).两种优化结构的键长、键角计算值接近,并大多与实验值相一致,说明计算方法正确,计算结果可靠.比较两种优化结构的总能量,α-BFBP的总能量远低于β-BFBP,从热力学角度考虑,α-BFBP的稳定性远高于β-BFBP.比较两种优化结构的HOMO能级,α-BFBP的HOMO能级低于β-BFBP,说明α-BFBP的抗氧化能力强于β-BFBP.比较两种优化结构的前沿轨道间的能量间隙,α-BFBP的能量间隙高于β-BFBP,说明α-BFBP的基态稳定性更好,电子难以激发.总之,量子化学计算结果很好地佐证了实验结果.分析标题化合物采取顺式构象是由丙基锯齿链折叠端方向所决定的.
A novel 1,3-bis (1-ferrocene sulfonyl-2-benzimidazole) propane (BFBP) was synthesized and its structure was characterized by IR, NMR, MS and X-ray single crystal diffraction The crystal structure is orthorhombic and the space group is Pnma. The unit cell parameters are: a = 1.30079 (13) nm, b = 2.9627 (3) nm, c = 1.01257 (10) nm, D = 1.492 g / cm3, μ = 0.907 mm-1, F (000) = 1816, Z = 4, R1 = 0.0506, wR2 = 0.1583. The crystal structure shows that the two ferrocenesulfonyl groups of the title compound, Which is the cis conformation rather than the trans conformation.Using the density functional theory and the B3LYP / 6-31G method, the geometrical optimization of the cis and trans conformations of the title compounds were carried out respectively, and two optimized structures α -BFBP (cis-optimized result) and β-BFBP (trans-optimized result) .The calculated values of bond length and bond angle of the two optimized structures are close to each other and mostly agree with the experimental data, which shows that the calculation method is correct and the calculation result is reliable. The total energy of α-BFBP is much lower than that of β-BFBP when compared with the total energy of the two optimized structures. From the thermodynamic point of view, the stability ofα-BFBP is much higher than that of β-BFBP.Comparing the HOMO energy levels of the two optimized structures, The α-BFBP has a low HOMO level β-BFBP, indicating that the antioxidant capacity of α-BFBP is stronger than that of β-BFBP.Comparing the energy gap between the frontier orbits of the two optimized structures, the energy gap of α-BFBP is higher than β-BFBP, indicating that the ground state of α-BFBP is stable In general, the results of quantum chemical calculations well support the experimental results.Analysis of the cis-conformation of the title compound by the orientation of the folded end of the propyl sawtooth chain.