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Ni(II) with mixed ligand of terephthalate-pyrazine (NiTP) metal complex can form metalorganic framework (MOF) material that offer many potential applications, such as adsorbent and/or photocatalyst for dye-based wastewater treatment. Production of the NiTP by hydrothermal method in a larger scale may economically unfavorable due to it requires high temperature and long reaction time. Green synthesis of NiTP by hydrothermal method using lower temperature and shorter reaction time was investigated in this study. The synthesis was done in Ni(II):T:P mol ratio of 1:1:4 at 150 ℃ for 10 hours. The NiTP complex was characterized by infrared spectroscopy and powder-XRD. Crystallinity degree, thermal stability, band gap energy, and pore volume of the NiTP complex were compared to that of Ni(II)-terephthalate (NiT) complex, which was also made using the same condition, to study the effect of pyrazine addition on the properties of the NiTP. This study finds that the green microcrystalline NiTP complex was successfully obtained from mild reaction condition in good yield and identical to known MOF compound of [Ni(μ3-ter)(μ2-pyr)]n.(ter = terephthalate; pyr = pyrazine). Although the synthesized NiTP complex has lower crystallinity degree compared to the NiT complex, but it has better thermal stability, lower band gap energy, and bigger pore volume; therefore, it is possible to be further developed as adsorbent and/or photocatalyst for wastewater treatment. [ABSTRACT FROM AUTHOR]

This research aims to incorporate pyrazine in the synthesis of Ni(II)-tartrate-pyrazine metal organic frameworks or Ni(II)-T-P MOF as candidate of porous material. Synthesis of the targeted MOF was conducted at room temperature in a methanolic solution by mixing Ni(II) solution, L-tartaric acid (T), and pyrazine (P) solutions sequentially in various molar ratios (Ni(II):T:P = 1:1:0; 1:0:2; 1:2:2; and 1:2:4) using two different Ni(II) salts (chloride and nitrate). Solid products were characterized by infrared spectroscopy, qualitative anion identification test, melting point test, and scanning electron microscopy. The result shows that type of nickel salt affects the precipitation of Ni(II) complex, in which pale blue solids were precipitated out only from the chloride reactions (1:0:2, 1:2:2, and 1:2:4). IR and SEM analyses from the 1:2:2 and 1:2:4 reactions show identical result as also shown by the 1:0:2 reaction, whereas qualitative anion identification test result suggests that the chloride is uncoordinated to the Ni(II). The targeted Ni(II)-T-P is unsuccessfully obtained, instead the product is proposed to be [Ni(pyrazine)x(H2O)(6-x)]Cl2. although the tartaric acid was doubled and firstly reacted with the Ni(II), the pyrazine still has higher preference to coordinate to the Ni(II) center than the tartrate ligand. [ABSTRACT FROM AUTHOR]