Novel metformin complexes: Geometry optimization, non‐isothermal kinetic parameters, DNA binding, on–off light switching and docking studies

Abstract

Novel three water‐soluble chromium(III) complexes of types [Cr(Cl)(gly‐H)2(met)H2O] (1), [Cr(Cl)(met)(pro‐H)2H2O] (2) and [Cr(Cl)(his‐H)2(met)H2O] (3) (met = metformin, gly = glycine, pro = proline and his = histidine) have been synthesized. The geometrical structures have been shown to be octahedral, with substantial evidence from spectroanalytical techniques. Thermal investigations show the degradation pattern of the compounds from which the kinetic and thermodynamic parameters for the complexes' degradation were calculated using the Coats–Redfern 13 distinct kinetic models. The quantum chemical parameters were computed using the energies of the molecular orbital structures, developed from optimized geometrical structures, to evaluate the stability of the complexes. The groove binding of the complexes with CT‐DNA was confirmed by absorption and emission spectroscopy, viscosity measurements, gel electrophoresis and molecular docking studies.

Water soluble Zinc(II) complexes: Geometrical, thermal, DNA/HSA/BSA binding, and cytotoxicity studies

“…The two complexes exhibit modified bands that correlate to the NH 2 and –C=N moieties of metformin stretching frequencies, implying metformin‐metal interaction. An additional band noticed at 1330 and 1,336 cm −1 in complexes 1 and 2 could be due to the arising of the chelate ring as a result of the bidentate type of interaction of metformin to the metal 25 . The neutralbidentate chelated amino acids (glycine/histidine) are accountable for the bands at 1622 and 1,621 cm −1 in complexes 1 and 2 26 .…”

“…An additional band noticed at 1330 and 1,336 cm À1 in complexes 1 and 2 could be due to the arising of the chelate ring as a result of the bidentate type of interaction of metformin to the metal. 25 The neutralbidentate chelated amino acids (glycine/histidine) are accountable for the bands at 1622 and 1,621 cm À1 in complexes 1 and 2. 26 According to the IR study, metformin and the auxiliary ligands associated with metal ions through the use of donor atoms that are oxygen and nitrogen.…”

Comments on multiple publications reporting single heating rate kinetics

“…The purpose of this note is to alert the Applied Organometallic Chemistry community to an alarming number of publications that report the single heating rate kinetics for thermal decomposition of compounds. According to Scopus, [ 1 ] most recently (i.e., in the years 2021 and 2022) this journal published 21 papers [ 2–22 ] that study the thermal decomposition kinetics as measured by thermogravimetry at a single heating rate. The resulting measurements are treated by means of the Coats–Redfern [ 23 ] or Horowitz–Metzger [ 24 ] method in order to evaluate the kinetic parameters, that is, the activation energy, E, preexponential factor, A, and reaction model, g(α) .…”