Multi-component hydrogen-bonding salts formed between imidazole and aromatic acids:Synthons cooperation and crystal structures  

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

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10期2115-2122,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (20701023, 20971076);the Natural Science Foundation of Shandong Province, China (BS2010NJ004,2009ZRB019KH)

摘　　要：Imidazole base was crystallized with different aromatic carboxylic acids 2,4-dihydroxybenzoic acid, 5-chlorosalicylic acid, and 1,8-naphthalic acid, affording three new binary molecular organic salts of [(C 3 H 5 N 2 + )·(C 7 H 5 O 4 )] (1), [(C 3 H 5 N 2 + )·(C 7 H 4 O 3 Cl )] C 7 H 5 O 3 Cl (2), and [(C 3 H 5 N 2 + ) (C 12 H 7 O 4 )] (3). Proton transfer occurs from the COOH of carboxylic acid to nitrogen of imidazole in all complexes (1-3), leading to the hydrogen bond N-H…O in all structures. To our knowledge, the recognition pattern between the carboxylic acid group and imidazole (acid-imidazole synthon) is less well-studied so far. The cooperation among COOH, COO and imidazolium cation functional groups for the observed hydrogen bond synthons is examined in the three structures. Generally, the strong N-H…O and O-H…O hydrogen bonds define supramolecular architecture and connectivity within chains, while weaker C-H…O hydrogen bonds play the dominant role in controlling the interactions between layers in these novel organic salts. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss.Imidazole base was crystallized with different aromatic carboxylic acids 2,4-dihydroxybenzoic acid, 5-chlorosalicylic acid, and 1,8-naphthalic acid, affording three new binary molecular organic salts of [（C 3 H 5 N 2 ＋ ）·（C 7 H 5 O 4 ）] （1）, [（C 3 H 5 N 2 ＋ ）·（C 7 H 4 O 3 Cl ）] C 7 H 5 O 3 Cl （2）, and [（C 3 H 5 N 2 ＋ ） （C 12 H 7 O 4 ）] （3）. Proton transfer occurs from the COOH of carboxylic acid to nitrogen of imidazole in all complexes （1–3）, leading to the hydrogen bond N–H…O in all structures. To our knowledge, the recognition pattern between the carboxylic acid group and imidazole （acid-imidazole synthon） is less well-studied so far. The cooperation among COOH, COO and imidazolium cation functional groups for the observed hydrogen bond synthons is examined in the three structures. Generally, the strong N–H…O and O–H…O hydrogen bonds define supramolecular architecture and connectivity within chains, while weaker C–H…O hydrogen bonds play the dominant role in controlling the interactions between layers in these novel organic salts. Thermal stability of these compounds has been investigated by thermogravimetric analysis （TGA） of mass loss.

关 键 词：crystal engineering supramolecular synthons IMIDAZOLE organic salts 

分 类 号：O626.23[理学—有机化学]