Investigation of the effect of polar functional groups on the crystal structures of indium MOFs

摘要: Three new In-MOFs with –NH2 and/or –NO2 functionalities are reported using 2-amino- (H2BDC-NH2), 2-nitro- (H2BDC-NO2) and 2-amino-5-nitroterephthalic acid (H2BDC-NH2/NO2). Their structures were determined from single crystal X-ray diffraction data. The structure of the first In-MOF composition [In(BDC-NH3)(BDC-NH2)]·1.6DMF·1.9H2O (In-BDC-NH2; DMF is dimethylformamide; space group P6222, a = b 14.738(2) A c 12.257(3) A) built up by two interpenetrating nets InO8 polyhedra interconnected BDC-NH22− ions to form framework qtz topology. Charge balance accomplished partial protonation amino group, which was confirmed IR spectroscopy. interpenetration leads decrease pore dimension (4.4 in diameter). Thermogravimetric analysis revealed stability 300 °C. Replacement H2BDC-NH2 H2BDC-NO2 reaction mixture led isoreticular MOF containing no groups but exclusively un- amino-functionalized linkers. Hence an indium mediated reduction linker molecule during solvothermal synthesis has occurred. use H2BDC-NH2/NO2 under exactly same conditions did not result formation MOF, changing parameters, –NH2/–NO2 bifunctionalised (DMA)2[In3(μ3-O)(BDC-NH2/NO2)4.5]·DMF (DMA dimethylammonium), denoted In-BDC-NH2/NO2, obtained. morphology can be altered cubic truncated octahedral crystals varying DMF/ethanol volume ratio synthesis. compound crystallises I3m, 24.8947(1) A, contains trinuclear {In3(μ3-O)} clusters interlinked BDC-NH2/NO22− super-tetrahedra. Four face-sharing super-tetrahedra ultra-tetrahedra connected final ncb topology isolated inaccessible pores.