Synthesis, Crystal Structure and Comparative DFT Studies of a 1D Ni(II) Polymeric Complex of 2-Hydroxypyridine-N-oxide

A novel Nickel (II) complex of 2-hydroxypyridine-N-oxide has been prepared and characterized by X-ray crystal structure analysis, FT-IR, UV spectra and thermogravimetry. The X-ray diffraction study reveals that the nickel complex is a 1D linear polymer in space group P ī with a = 6.250(1), b = 8.746(2), c = 9.462(2) Å, α = 81.76(3) o , β = 79.55(3) o and γ = 81.17(3) o . Two nickel ions are present in the unit cell related by the crystallographic centre of symmetry at ½ ½ ½. There are two different short non-bonded Ni to Ni separations in the polymeric structure: 3.454 and 3.467 Å respectively. Both room temperature magnetic moment measurements, and theoretical calculations are in favor of a simple paramagnetic system. As a complementary study, plane wave pseudopotential DFT calculations were performed, utilizing eight different XC functionals. The PBE and PBE0 functionals reproduce well the X-ray crystal structure of the complex, while the HSE functional gives a band gap which corresponds reasonably to the experimentally estimated value. The results of antimicrobial properties and thermal analysis of the complex are also reported. Graphical Abstract The preparation, crystallization and X-ray analysis of a novel 1D polymeric Nickel (II) complex of 2-hydroxypyridine-N-oxide and its characterization by FT-IR, UV spectra, thermogravimetry and possible therapeutics via antimicrobial studies are described.