1. Solvent-mediated assembly of chiral/achiral hydrophilic Ca(II)-tetrafluoroterephthalate coordination frameworks: 3D chiral water aggregation, structural transformation and selective CO2 adsorption.
- Author
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Sheng-Chun Chen, Feng Tian, Kun-Lin Huang, Cheng-Peng Li, Jing Zhong, Ming-Yang He, Zhi-Hui Zhang, Hong-Ning Wang, Miao Du, and Qun Chen
- Subjects
COORDINATION compounds ,CHIRALITY ,SOLVENTS ,CHEMICAL reactions ,CHEMICAL research - Abstract
The spontaneous self-assembly reactions of 2,3,5,6-tetrafluorobenzenedicarboxylic acid (H
2 BDC-F4 ) with Ca(NO3 )2 ·4H2 O in different solvents resulted in the generation of hydrophilic 3D chiral and achiral Ca(II)-organic frameworks {[Ca4 (BDC-F4 )4 (H2 O)4 ]·4H2 O}n (1) and [Ca(BDC-F4 )(MeOH)2 ]n (2), respectively. Complex 1 exhibits higher water solubility compared to 2, and further dissolution of 1 in water results in a new achiral crystal, [Ca(BDC-F4 )(H2 O)4 ]n (3). All complexes have been characterized by elemental analysis, IR spectroscopy, and single-crystal and powder X-ray diffraction techniques. Complex 1 crystallizes in the tetragonal P41 21 2 chiral space group and features a rare binodal 5-connected network, directed by a unique 3D chiral (10,3)-a water aggregation consisting of two distinct helical arrays. Complex 2 crystallizes in the space group C2/c and has a binodal 4-connected pts net. Complex 3 crystallizes in the space group P21 /m and presents a 2D layer framework containing the unprecedented polymeric [CaII -H2 O]n chain based on triple μ2-O aqua bridges. The structural discrepancies illustrate the solvent-induced effect on the construction and structural transformation of chiral and achiral coordination frameworks. Moreover, gas (N2 and CO2 ) adsorption studies show that the dehydrated framework 1a exhibits excellent selective CO2 gas uptake at 195 K. [ABSTRACT FROM AUTHOR]- Published
- 2014
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