Construction of Zn(II) microporous metal–organic frameworks based on 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate

Abstract

Three novel microporous zinc MOFs, [Zn3(EBTC)2]∙2(CH3)2NH2∙0.5DMSO∙3H2O (1), [Zn(EBTC)0.5(BPY)]∙2DMSO∙0.5DMF∙2H2O (2) and [Zn2(EBTC)(BPP)2]∙3DMSO∙2DMF∙5H2O (3) (EBTC=1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate, BPY=4,4′-bipyridine, BPP=1,3-bi(4-pyridyl)propane), have been synthesized under solvothermal conditions. The versatile coordination modes of EBTC are the key to such diverse MOFs. The results of X-ray single diffraction analyses indicate that 3D microporous MOF 1 with fla topology possesses 2D [Zn3(EBTC)2]∞ layer built from 1D double-chain-like motif containing trinuclear [Zn3(COO)8]2− SBUs, in which the two phenyls of EBTC are almost perpendicularly arranged. Compound 2 is a 3D layer-pillar structure with Zn(II) ions bridged by planar EBTC to generate 2D [Zn(EBTC)0.5]∞ sheet, and the 2D sheets are further pillared by rigid BPY to form a 3D porous framework with fsc topology. Complex 3 exhibits a 3D 2-fold interpenetrating framework with (4.64.8)2(42.64) topology, in which the flexible BPP links the 1D [Zn2(EBTC)]∞ ladder to form a 2D [Zn2(EBTC)(BPP)2]∞ structure with large 1D channels, which leads the flexible 2D framework to 2-fold interpenetration and forms a 3D porous network. Complexes 1 and 3 exhibit good luminescent properties around the blue-violet region.