Department of Chemistry
Permanent URI for this community
Browse
Browsing Department of Chemistry by Author "Batisai, Eustina"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Open Access Synthesis and Characterisation of Porous Mixed-Ligand Metal-Organic Frameworks for Sorption Studies(2022-07-15) Mbonzhe, Luccile; Batisai, Eustina; Oliver, CliveMetal-organic frameworks (MOFs) have been identified as promising physisorption candidates because of their unique structures. MOFs are a class of crystalline materials consisting of coordinate bonds between metal ions and organic ligands. The permanent porosity of MOFs enables them to be applied as gas storage and, carbon capture and utilization materials. The main portion of this study describes the synthesis of new porous MOFs from simple building blocks. A total of four (4) organic ligands, namely; N,N’–bis–(3-pyridylmethyl)–benzophone diimide (L1), N,N’–bis–(3-pyridylmethyl)–biphenyl diimide (L2), N,N’–bis(pyridin-4–ylmethyl) naphthalene diimide, N,N’–bis–(3-pyridylmethyl)–biphenyl diimide (L3) and N,N’–bis(gly)–biphenyl diimide (L4) were successfully synthesized and characterized. The second part of this study describes the synthesis of five (5) new MOFs, namely; {[Zn2(OBZ)2(L2)]ꞏ(DMF)3}n (LMMOF01), {[Zn(TPA)(L4)0.5]ꞏ(DMF)2}n (LMMOF02), {[Co3(TPA)3(L1)]ꞏ(DMF)4}n (LMMOF03), {[Co(BYP)(L4)]ꞏ(H2O)}n (LMMOF04) and {[Cu(L4)0.5]ꞏ(DMF)}n (LMMOF05). The MOFs were synthesized from the reactions of the pyridyl N-donor diimide ligands, carboxylate O-donor co-ligands (terephthalic acid (TPA), 4,4-oxybis benzoic acid (OBZ) and 2,2-bipyridy (BPY)) and transition metal salts. The MOFs were characterized using single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD) and variable temperature (VT-PXRD). The thermal stability of MOFs was determined using thermogravimetric analysis (TGA) and hot stage microscopy (HSM). SCXRD revealed that LMMOF01 and LMMOF03 are 3-D, LMMOF02 is 2-D while LMMOF04 and LMMOF05 are 1-D. The 2-D and 3-D MOFs possess channels that are occupied by the solvent molecules. The porosity of the MOFs was tested using carbon dioxide, nitrogen and hydrogen gases.Item Open Access Synthesis of mixes ligand metal-organic frameworks for sorption studies(2021-04) Mahwasane, Rolivhuwa; Batisai, Eustina; Oliver, CliveMetal-organic frameworks (MOFs) are a class of crystal engineered materials consisting of organic and inorganic units. They are made up of metal ions connected by bridging ligands to form three dimensional (3D) networks. MOFs have attracted widespread interest owing to their diverse applications in gas storage and separation, luminescence, catalysis, non-linear optics as well as magnetism. The first part of this study describes the synthesis and characterisation of five pyridyl N-donor diimide ligands namely; N,N-bis(pyridin-3-ylmethyl)naphthalene diimide (L1), N,N-bis(pyridin-4-ylmethyl) naphthalene diimide (L2), 2,2-bis(pyridin-2-ylmethyl)-[5,5-biisoindoline]-1,1-3,3-tetraone (L3), 2,2-bis(pyridin-4-ylmethyl)-[5,5-biisoindoline]-1,1-3,3-tetraone (L4) and 5,5-carbonylbis(2-(pyridin-3-ylmethyl) isoindoline-1,3-dione) (L5). The second part of this study describes the synthesis of seven (7) new MOFs namely; {[Zn(DCT)(L1)0.5]·(DMF)}n (RMMOF 1), {[Zn(DCT)(L2)0.5]·(DMF)·(H2O)}n (RMMOF 2), {[Co(DCT)(L2)0.5]·(DMF)}n (RMMOF 3), {[Zn5(OBZ)3(DMF)2]·(DMF)4}n (RMMOF 4), {[Cd(NDC)(L4)2]·(DMF)3}n (RMMOF 5), {[Zn0.5(NDC)0.5(L4)0.5]·(DMF)2}n (RMMOF 6) and {[Cu(NDC)(L5)0.5](DMF)3}n (RMMOF 7). The MOFs were synthesized from the reactions of the pyridyl N-donor diimide ligands, carboxylate O-donor co-ligands (6,6-dithiodinicotinic acid (DCT), 4,4-oxybis benzoic acid (OBZ) and 2,6-naphthalene dicarboxylic acid (NDC)) and transition metal salts. The MOFs were characterized using single crystal X-ray diffraction (SCXRD), thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and Brunauer-Emmet-Teller (BET). SCXRD revealed that the MOFs are three dimensional and possess voids that are occupied by solvent molecules. The nature of the voids as well as the void volumes were determined using the Mercury program. RMMOF 7 possesses the largest void space (~33%) compared to the other MOFs. The sorption capacities were determined for RMMOF 4, RMMOF 5, RMMOF 6 and RMMOF 7 using carbon dioxide gas at 195 K and 273 K. RMMOF 7 adsorbs the largest amount of CO2 at 195 K compared to the other MOFs.