| Analogous diazamesocycles 1,4-diazacycloheptane (DACH) and piperazine (PIPO) bases were rationally chosen to crystallize with a range of organic acids (including aromatic and alkyl carboxylic acids), affording two series of binary charge-assistant co-crystals, which are characterized and structurally dicussed in this work.In chapterⅡ, sixteen diamine carboxylate are synthesized through self-assembly of DACH or PIPO with multiple carboxylic acids. The resultant compounds are as follows: [H2DACH]·[OA](1a), [H2PIPO]·[OA]·H2O(1b), [H2DACH]·[FA] (2a), [H2PIPO]·[FA] (2b), [H2DACH]·[TA] (3a), [H2PIPO]·[TA](3b), [H2DACH]·[PNA]2 (4a), [H2PIPO]·[PNA]2(4b), [H2DACH]·[NDA]·3H2O(5a-1), [H2DACH]·[HNDA]2·(H2O)·(CH3OH) (5a-2), [H2PIPO]·[NDA]·H2O (5b), [H2DACH]·[HTMA]·H2O(6a), [H2PIPO]·[H2TMA]2(6b), [H2DACH]2·[BTA]·2.5H2O (7a-1), [H2DACH]2·[BTA]·4.5H2O (7a-2), and [H2PIPO]2·[BTA]·6.5H2O (7b). All the prepared co-crystals have a common feature of the occurrence of the proton-transfer between acid and base. Strong N-H...O interactions are involved in these co-crystals, undoubtedly following the best donor/acceptor guidelines.And in chapterⅢ, four PIPO related compounds are obtained under general conditions. they are [(H2PIPO)·(HBTC)] (17), [(H2PIPO)·(HA)] (18), [(H2PIPO)·(HCA)·H2O] (19), [(H2PIPO)·(PA)·3H2O] (20). Proton-transfer has also been detected in these compounds.X-ray single-crystal diffraction studies reveal that the stronger N-H...O and O-H...O interactions, are the driving forces for the construction of the hydrogen-bonding networks in these compounds. Thus, 1D chain structure, 2D framework and 3D framework are constructed in these compounds by multiple hydrogen bonds. Thermogravimetric analysis (TGA) of mass loss for twenty compounds has been measured in this work. The similarity in motifs of aromatic or alkyl dicarboxylic acid with DACH and PIPO functional groups is extended to synthons for prospering crystal engineering. |
PDF Full Text Request