A nickel glutamate metal biomolecule framework

Abstract

This paper describes the synthesis of a MbioF (Metal-biomolecule Framework) using glutamic acid and nickel carbonate as precursors. The direct action of glutamic acid (H₂Glu) on basic nickel carbonate (NiCO₃·2Ni(OH)₂·4H₂O) initially indicated the formation of a complex, [Ni(HGlu)₂], which was then treated in a Teflon-lined stainless steel autoclave at 100 °C for 24 hours, resulting in the compound {[Ni(Glu)(H₂O)]·H₂O}_n, with a yield of 43%. The resolution of the structure of this compound by single-crystal X-ray diffraction indicated that it belongs to the orthorhombic crystal system and space group P2₁2₁2₁, with a structure analogous to those of the compounds {[Co(Glu)(H₂O)]·H₂O}_n, {[Cu(Glu)(H₂O)]·H₂O}_n and {[Zn(Glu)(H₂O])·H₂O}_n described in the literature, with a molecular formula of C₅H₉NO₅Ni·H₂O, molar mass of 239.8379 g mol^-1, parameters a, b and c with values of 7.0577(2) (Å), 10.2307(3) (Å) and 11.5350(4) (Å), and a volume of 837.219 ų. This compound, which is an intensely green crystalline solid, was characterized by electron (UV-Vis) and vibrational spectroscopy in the Fourier Transform Infrared (FTIR) region, powder X-ray diffractometry (PXRD) and thermogravimetric analysis (TGA/DTA). The in vivo toxicity and in vitro antimicrobial activity of the complex and the Ni-MOF were tested. The two compounds presented no toxicity at a concentration of 5000 μg mL^-1, and showed inhibitory activity at 64 μg mL^-1 in 24 h and at 128 μg mL^-1 in 48 h against the yeast Candida albicans.