半葫芦[6]脲的合成及其晶体结构

Synthesis and crystal structure of hemicucurbit[6]uril

半葫芦[6]脲空腔高度是葫芦[6]脲一半,其性质与葫芦[6]脲相差较大,所以分析其结构非常重要。以乙烯脲和甲醛为反应物,在硫酸催化下合成半葫芦[6]脲,采用IR、NMR、MS和X-射线单晶衍射分析对其结构进行了表征。结果表明,半葫芦[6]脲的晶体结构为三斜晶系,P-1空间群,晶体结构参数为:a=0.886 40(14)nm,b=0.894 06(15)nm,c=1.143 93(18)nm,α=101.136(6)(°)、β=108.896(13)(°)、γ=97.109(18)(°),V=0.824 4(2)nm3,R=0.035 9,wR=0.092 1,组成为C24H50N12O13,相对分子质量为714.76。晶体结构中相邻半葫芦[6]脲羰基氧与乙烯脲环上的亚甲基氢存在氢键。

The cavity height of hemicucurbit [ 6 ] uril is a half of the cucurbit [ 6 ] and the chemical properties of the two compounds are significantly different. Thus it is important to understand the structure characteristics of hemicucurbit [ 6 ] uril. Hemicucurbit [ 6 ] uril was synthesized with ethylene urea and formaldehyde catalyzed by sulfuric acid. The structure was characterized by IR, NMR, MS, and X-ray diffraction. The results indicate that the crystal structure of hemicucurbit [ 6 ] uril is triclin- ic system and space group P-1, and the crystal structure parameters are a=0.88640（14）nm,b=0.89406（15）nm,c=1.14393（18）nm,α=101.136（6）（°）、β=108.896（13）（°）、γ=97.109（18）（°）,V=0.8244（2）nm3,R=0.0359,wR=0.0921. Its empirical formula is C24HsoNI2 O13 and formula weight 714.76. In crystal structure of hemicucurbit[ 6 ] uril, there is hydrogen bond between adjacent ketonic oxygen and methyl radical hydrogen on ethylene urea link .