Structural diversification and single-crystal-to-single-crystal transformation of alkaline earth metal-based MOFs regulated by solvent effect. Issue 16 (29th March 2016)

• Record Type: Journal Article
• Authors: Wang, Xi; Hu, Min; Tian, Jia-Yue; Liu, Chun-Sen
• Is Part Of: CrystEngComm. Volume 18:Issue 16(2016)
• Page Start: 2864
• Page End: 2872
• Publication Date: 2016-03-29
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c6ce00552g
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : We herein discuss the structural diversity and potential SCSC conversion based on four alkaline–metal coordination networks modulated by the solvent effect. Abstract : Two pairs of alkaline earth metal-based MOFs have been synthesized by spontaneous self-assembly reactions of Mg(ii ) or Ca(ii ) and two tricarboxylate ligands, H3 BTTB and H3 TCM (H3 BTTB = 4, 4′, 4′′-[benzene-1, 3, 5-triyl-tris(oxy)]tribenzoic acid; H3 TCM = 4, 4′, 4′′-{[(2, 4, 6-trimethylbenzene-1, 3, 5-triyl)tris(methylene)]tris(oxy)}tribenzoic acid), in different solvent media. The Mg/BTTB assemblies, {[Mg3/2 (BTTB)(H2 O)(DMF)](DMF)} n (1 ) (DMF = N, N ′-dimethylformamide) and {[Mg3/2 (BTTB)(DMAc)2 ](DMAc)0.5 } n (2 ) (DMAc = N, N ′-dimethylacetamide), are prepared in DMF/H2 O and DMAc/H2 O media, respectively, and feature uniform kgd -type 2D bilayer structures but with different compactness. Meanwhile, two Ca/TCM assemblies, {[Ca5/2 (TCM)2 (DMF)2 (H2 O)](Me2 NH2 )(DMF)2 (H2 O)} n (3 ) and {[Ca3 (TCM)2 (DMAc)3 (H2 O)2 ](DMAc)5 } n (4 ), have been achieved in DMF/H2 O and DMAc/H2 O mixed systems as well. However, compounds3 and4 have an enormous structural discrepancy, that is, compound3 shows a complicated parallel 2D → 3D polycatenaned supramolecular architecture while4 exhibits a 2-fold interpenetrating sit -type 3D framework. These various coordination patterns evidently illustrate the solvent regulation on the alkaline earth metal-based MOFs. The single-crystal-to-single-crystal structural transformation experiment reveals that the loose kgd -network compound2 can be converted into the compact isoreticular compound1 when immersed in DMF for 12 h. However, the reversed conversion cannot be realized. In addition, their thermal stability, gas adsorption, and solid-state fluorescence properties have also been investigated.