量子化学计算苄嘧磺隆的晶体结构

制备苄嘧磺隆的单晶并用X射线衍射测定晶体结构。苄嘧磺隆晶体属于单斜晶系,C2/c空间群。晶胞参数为:a=33.831(7),b=6.902 0(14),c=16.021(3),α=90.00(3)。,β=104.48(3)。,γ=90.00(3)°,V=3 622.1(13)~3。晶体分子内通过N-H…N氢键和C-H…0氢键形成2个六元环,使分子结构较稳定。苯环平面和嘧啶环平面之间的夹角为50.00(15)°。晶体以1中心对称二聚体为基本重复单元。2个分子间以N-H…O氢键和C-H…O氢键连接。晶体由这些二聚体以范德华作用力堆积而成。使用Gaussian 03程序,用B3LYP/6-31G(d,p)法计算分子的优化结构、电荷分布、稳定性、前沿轨道布居分析和3D示意图。算得分子的键长键角数据和X射线衍射的晶体结构数据基本相符。键长和键角的计算值与X射线衍射数据之差证实晶体中分子间的氢键。

Quantum chemical calculation of the crystal structure of bensulfuron-methyl

The single crystal of bensulfuron-methyl was cultured and the crystal structure was determined by X-ray diffraction.Thecrystal belongs to monoclinic C2/c,with a=33.831(7)(A),b=6.902 0(14) (A),c=16.021(3) (A),α=90.00(3)°，β=104.48（3）°，γ=90.00(3)°,V=3622.1(7)(A)~3.In the crystal,the intramolecular N-H… and C-H…O hydrogen bonds result in the formation of two six-membered rings,which may be effective in the stabilization of the struetum.The dihedral angle between the benzene and pyrimidine rings is 50.00(15)°.Between two molecules,there are intermolecular N-H…O and C-H…O hydrogen bonds to form centrosymmetric dimers.The optimized structure,charge distribution,molecular stability,HOMO,LUMO,composition of frontier or-bitals,population analysis and three-dimensional schematic diagram were calculated by B3LYP/6-31G(d,P)method.The resultshows that the bond lengths and bond angles obtained by quantum chemical calculation were almost the same with the values of X-raydiffraction.The difference between the two methods confirmed the intermoleeular hydrogen bonds in the crystal structure.