Novel Metal-Organic Framework Based on Cubic and Trisoctahedral Supermolecular Building Blocks: Topological Analysis and Photoluminescent Property

A novel supermolecular building blocks (SBBs) based metal-organic framework (MOF), with formula [Zn-7(TMBHB)(2)center dot 2NO(3)center dot 5DMF center dot 4CH(3)CH(2)OH center dot 6H(2)O](n) (SDU-1), was constructed from C-3-symmetric trimethyl substituted 3,3',3,5,5',5-benzene-1,3,5-triylhexabenzoic acid (H6TMBHB). Notably, the SDU-1 consists of two kinds of rare secondary building units (SBUs), [Zn-2(COO)(3)] and [Zn-2(COO)(4)], which are linked by TMBHB to form cubic and trisoctahedral SBBs, respectively. TOPOS software analysis of SDU-1 indicates that two alternative simplifications based on different SBBs can produce (3,24)-connected rht or (4,12)-connected ftw topologies. Compared with a recently reported Zn-BHB (H6BHB = 3,3',3,5,55-benzene-1,3,5-triylhexabenzoic acid) MOF, the structural dissimilarity between them was caused by the steric hindrance of three methyl groups, which makes three isophthalate units on TMBHB nearly perpendicular to the central phenyl ring, giving TMBHB a nonplanar conformation. The photoluminescence behavior of SDU-1 was also discussed.