N-(嘧啶-2-基)-N'-乙氧酰基硫脲的合成、晶体结构及量子化学

以2-氨基嘧啶、硫氰酸钾和氯甲酸乙酯为原料,在乙酸乙酯中合成了N-(嘧啶-2-基)-N'-乙氧酰基硫脲,用元素分析和红外光谱对化合物结构进行了表征。采用缓慢蒸发溶剂法在室温下于二甲基甲酰胺溶剂中培养出化合物单晶。晶体结构分析表明,化合物属于单斜系,P21/n空间群,晶胞参数为a=0.49095(19)nm,b=1.5143(6)nm,c=1.4071(6)nm,β=94.047(8)°,V=1.0435(7)nm3,Z=4,Dc=1.453g/cm3,μ=0.297mm-1,F(000)=480,R1=0.0526,wR2=0.1556。化合物分子中只存在2个分子内氢键,氢键及静电引力的共同作用使得化合物呈现复杂的空间结构。运用Gaussian 03程序,在6-311G的基组水平上,用HF、MP2以及B3LYP3种方法对标题化合物进行了几何全优化,并对其成键情况、自然键轨道(NBO)、分子总能量及前沿轨道能量进行了分析,结果表明,化合物中的硫脲基团及嘧啶环是主要的活性中心。

DOI:10.3724/SP.J.1095.2010.00127Synthesis,Crystal Structure and Theoretical Calculation of N-(Pyrimidin-2-yl)-N′-ethoxylacyl Thiourea

A new compound of N-(pyrimidin-2-yl)-N′-ethoxylacyl thiourea was synthesized by mixing 2-amino-pyrimidine, potassium thiocyanate and ethyl chloroformate in ethyl acetate, and the structure was characterized by elemental and IR analysis. Single crystals suitable for X-ray measurement were obtained by slow evaporation of dimethylformamide at room temperature. The compound crystallizes in the monoclinic space group P21/n and has a=0.49095(19) nm, b=1.5143(6) nm, c=1.4071(6) nm, β=94.047(8)°, V=1.0435(7) nm3, Z=4, Dc=1.453 g/cm3, μ＝0.297 mm-1, F(000)=480, R1=0.0526, wR2=0.1556. There are two intramolecular hydrogen bonds. The synergetic interaction between the electrostatic attraction and hydrogen bondings is responsible for the packing of the compound into three-dimensional network. A crystal unit of the title compound was selected as the initial structure, and it was fully optimized by HF/6-311G, MP2/6-311G and B3LYP/6-311G methods in Gaussian 03 package, the atomic charges, natural bond orbital(NBO), total energy and frontier orbital energy were also discussed, and the thiourea and pyrimidine ring are the active center.