摘要
合成一种新的尿素 -阴离子复合主体晶格包合物 ,( C2 H5) 4N+[C4H2 O2 - 4 ]1 / 2 · CO( NH2 ) 2 · H2 O,并进行了 X射线晶体结构分析 .晶体为单斜晶系 ,C2 / c( No.1 5 )空间群 ,a=1 .790 9( 5 ) nm,b=1 .4 431 ( 4 ) nm,c=1 .4 443( 3) nm,β=1 2 6 .76 ( 2 )°,V=2 .990 5 ( 1 3) nm3 ,Z=4 ,R1 =0 .0 6 4 7,w R=0 .0 735 .包合物中 ,两个尿素分子通过一对 N— H… O氢键以通常的“肩并肩”方式连接起来 ,形成一个二聚体 .这些二聚体沿 c轴方向依次排列 ,每两个相邻二聚体间生成的氢键将它们连接成一个沿 ( 0 0 1 )方向延伸的锯齿形扭带 .由 c滑移面相关连的富马酸阴离子以水分子为桥 ,由 O( W)— H… O氢键连成一条宽带 ,沿 c轴方向延伸 .这些富马酸根 -水分子复合氢键宽带与尿素纽带交替平行排列 ,由此形成了一个平行于 ac面的氢键层 .四乙基铵离子层填充在 b=1 / 4和 b=3/ 4处的主体晶格的层间空隙处 ,构成“三明治”式夹层结构的包合物 .
A new inclusion complex, (C 2H 5) 4N +[C 4H 2O 2- 4] 1/2·CO(NH 2) 2·H 2O, has been prepared and characterized by X-ray crystallography. Crystal data: space group C 2/c(No.15), a=1.790 9(5) nm, b=1.443 1(4) nm, c=1.444 3(3) nm, β=126.76(2)°, V=2.990 5(13) nm 3, Z=4, F(000)= 1 168, \{μ=\}0.09 mm -1, R 1=0.064 7 for 2 088 observed Mo Kα data (|F| 2≥2.0σ|F| 2). In the crystal structure of the title compound, two urea molecules are linked by a pair of N-H...O hydrogen bonds in the usual shoulder-to-shoulder manner to generate a dimer. These hydrogen-bonded urea dimers are alternately linked by additional pairs of N-H...O hydrogen bonds to form an approximately planar ribbon oriented parallel to the c axis. Bridged alternately by donor O(W)-H...O hydrogen bonds from the water molecules, the fumarate anions form a zigzag wide ribbon running parallel to the c axis. The parallel, alternate arrangement of these two kinds of complementary ribbons facilitates cross-linkage by N-H...O hydrogen bonds to form a puckered anionic layer normal to b axis. The title complex features a sandwich-like structure in which the tetraethylammonium cations occupy the space between urea-fumarate-water layers.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第12期2296-2299,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金 (批准号 :2 99730 0 5 )资助
