Strong and Weak Hydrogen-Bonding Interactions in the Structures of N,N',N' '-Trisubstituted Guanidinium Chlorides and Bromides

详细信息    查看全文

• 作者：Farouq F. Said ; Tiow-Gan Ong ; Glenn P. A. Yap ; and Darrin Richeson
• 刊名：Crystal Growth & Design
• 出版年：2005
• 出版时间：September 2005
• 年：2005
• 卷：5
• 期：5
• 页码：1881 - 1888
• 全文大小：331K
• 年卷期：v.5,no.5(September 2005)
• ISSN：1528-7505

文摘

The reaction of two trisubstituted guanidines N,N',N' '- triisopropylguanidine (TPG) and N,N'-diisopropyl-N' '-2,6-dimethylphenylguanidine (DPArG) with HX or equivalents (X = Cl, Br) yielded the anticipatedguanidinium halide salts. The structures of TPGH⁺X^- (X = Cl, 1), TPGH⁺X^-·H₂O (X = Br, 3·H₂O), and DPArGH⁺X^-(X = Cl, 2; Br, 4) were determined by single-crystal X-ray diffraction analysis to examine the potential intermolecularinteractions in these compounds and their influence on the extended structures that were observed. The formationof strong, charge-assisted hydrogen bonds, NH⁺···X^-, dominates the extended structures. In addition, weakerinteractions between the N-substituents and between the X^- anions and CH bonds of the substituents have anapparent role in the structures of these materials. While the TPGH⁺ cation displayed a C₃ propeller-type orientationin the structures of 1 and 3·H₂O, two different isomeric forms for the less symmetric DPArGH⁺ cations were observed,and the identity of the anion and of the substituents both appear to be important in determining which form isobtained. Although the DPArGH⁺ cation exhibited different isomeric structures in 2 and 4, a common structuralmotif consisting of hydrogen-bonded chains was observed in their solid-state structures.