Co-crystallization of glycine anhydride with the hydroxybenzoic acids: Controlled formation of dimers via synthons cooperation and structural characterization  

作　　者：WANG Lei ZHAO Lei LIU WeiMing CHEN RuiXin GU YuanXiang YANG Yu 

机构地区：[1]Key Laboratory of Eco-Chemical Engineering,Ministry of Education,College of Chemistry and Molecular Engineering,Qingdao University of Science and Technology,Qingdao 266042,China

出　　处：《Science China Chemistry》2012年第11期2381-2387,共7页中国科学（化学英文版）

基　　金：financially supported by the National Natural Science Foundation of China (20701023, 51102138);the Natural Science Foundation of Shandong Province, China (BS2010NJ004,2009ZRB019KH)

摘　　要：The results of crystallographic analyses on 1：1 and 1：4 well-defined co-crystals formed between glycine anhydride and each of 4-hydroxybenzoic acid and 3,5-dihydroxybenzoic acid are described. Neutral molecules are connected via heteromeric O-H.-.O and N-H…O contacts leading to different packing arrangements of supramolecular chains. On the basis of the molec- ular structures of glycine anhydride and carboxylic acid guests, the hydrogen bonds are arranged to give centrosymmetric synthons V and VII which are noteworthy for their robustness. Hydrogen-bond interactions between glycine anhydride and aromatic acid provide sufficient driving force to direct molecular recognition and crystal packing. Utilization of the orientation of functional groups of the building blocks, the acidity, and weak interactions provides a route for the creation of novel supra- molecular architectures in the crystal lattice. Both two co-crystals contain the expected hydrogen-bonded motifs, and there has been no proton transfer from either of the two carboxylic acids to the aza compound moiety. This demonstrates that glycine anhydride is very capable of affecting the construction of binary co-crystals in a predictable and rationale manner. It is noted that synthons Ⅷ and IX are fairly large, but the real challenge in crystal engineering is to find a big enough synthon that occurs often enough. Thermal stability of these compounds has been investigated by thermogravimetric analysis （TGA） of mass loss.The results of crystallographic analyses on 1:1 and 1:4 well-defined co-crystals formed between glycine anhydride and each of 4-hydroxybenzoic acid and 3,5-dihydroxybenzoic acid are described. Neutral molecules are connected via heteromeric O-H···O and N-H···O contacts leading to different packing arrangements of supramolecular chains. On the basis of the molecular structures of glycine anhydride and carboxylic acid guests, the hydrogen bonds are arranged to give centrosymmetric synthons V and VII which are noteworthy for their robustness. Hydrogen-bond interactions between glycine anhydride and aromatic acid provide sufficient driving force to direct molecular recognition and crystal packing. Utilization of the orientation of functional groups of the building blocks, the acidity, and weak interactions provides a route for the creation of novel supra- molecular architectures in the crystal lattice. Both two co-crystals contain the expected hydrogen-bonded motifs, and there has been no proton transfer from either of the two carboxylic acids to the aza compound moiety. This demonstrates that glycine anhydride is very capable of affecting the construction of binary co-crystals in a predictable and rationale manner. It is noted that synthons VⅢ and IX are fairly large, but the real challenge in crystal engineering is to find a big enough synthon that occurs often enough. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss.

关 键 词：CO-CRYSTALS crystal structure supramolecular synthons glycine anhydride 

分 类 号：O631.3[理学—高分子化学]