Homonuclear nickel(II) metal-organic framework-type supramolecule: adsorption and emission properties

Coordination-driven self-assembly of nickel (II) ions with equimolar amounts of 1, 10 phenanthroline, and benzoic acid was used to create homonuclear nickel (II) MOF-type supramolecule. Single crystal X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, photoluminescence measurement, FT-IR, UV-visible spectroscopy, and nitrogen physisorption measurement were used to characterize the compound. The single crystal X-ray diffraction study reveals that the synthesized compound is two-dimensional with pores in the structure. The homonuclear nickel (II) MOF-type supramolecule crystallized in a triclinic crystal system, with space group P-1 (No.2) and unit cell parameters a = 9.2053(4) Ǻ, b = 13.2964(5) Ǻ, c = 15.8998(6) Ǻ, α = 66.296(2) °, β = 89.400(2) °, γ = 89.441(2) °. The crystal structure result shows π-π and intermolecular interactions between adjacent 1, 10-phenanthroline molecules. DSC result showed a gradual decomposition confirming thermal stability of the compound. The emission (468 nm) spectrum result shows energy peaks of a typical multiphonon phase, indicating luminescence process. The surface topology and single absorption maximum at 308 nm reveal formation of a distorted octahedral structure. Brunauer-Emmett-Teller and Langmuir surface area results 383.741 and 975.830 m²g^-1, respectively, indicate high adsorption capacity. Langmuir isotherm model result of the compound shows an efficient adsorption property for storing energy. The excellent nickel (II) MOF-type supramolecule adsorption capacity and emission property opened the door to its use in energy storage applications especially in photovoltaic cells.