New Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) Gibberellate Complexes: Synthesis, Structure, and Inhibitory Activity Against COVID-19 Protease.

Transition metals such as Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) have been reacted with gibberellic acid (HGA) to give novel complexes, and those have been characterized by physical, spectral and analytical methods. The plant hormone gibberellate acts as a deprotonated bidentate ligand in the complexation reaction with central metal ions in the ratio 1 : 2 (M n+ : GA). The complexes [M(GA)2(H2O)2], where [M = Mn(II), Co(II), and Ni(II)] form octahedral structures, while [M(GA)2] complexes [M = Zn(II), Cd(II), and Hg(II)] display four-coordination geometry. The octahedral structures of Cr(III) and Fe(III) complexes are characterized by the general formula [M(GA)2(H2O)(Cl)]. Computational study carried out has determined possible interactions of the complexes with COVID-19 (6LU7).

Exploring interaction dynamics of designed organic cocrystal charge transfer complex of 2-hydroxypyridine and oxalic acid with human serum albumin: Single crystal, spectrophotometric, theoretical and antimicrobial studies.

As human serum albumin (HSA) being the most abundant blood protein involved in the role of transport of molecules (drugs), we have designed HSA binding organic charge transfer complex between 2-hydroxypyridine (donor) and oxalic acid (acceptor) showing antimicrobial activities. The type of interactions between HSA and synthesized complex at the molecular level was studied through fluorescence spectroscopy. Binding constant along with the type of quenching mechanism was shown through the Stern Volmer equation. Molecular docking tool also justifies the binding results obtained from fluorescence by providing different interactions, FEB, hydrogen bonding and H-bonding surfaces. Antimicrobial activity was screened against three bacteria - Escheichia coli, Bacteria subtilis and Staphylococus aureus strain and three fungi - Aspergillus Niger, Candida Albicans and Fusarium Oxysporun using disc diffusion method. The characterization of the complex was done through different techniques (FTIR, UV-vis spectroscopy, TGA-DTA). Job's method along with single crystal XRD provides 2:1 stoichiometry and O⋯H-O type of H-bonding between acceptor and donor molecule. Physical parameters (KCT, εCT, ID, ΔG°, µEN, f and RN) were also calculated for the synthesized complex. Theoretical computational data (DFT and Hirshfeld surface) have also been calculated for the complex.

Synthesis, characterization, antimicrobial and DNA binding properties of an organic charge transfer complex obtained from pyrazole and chloranilic acid.

The chemistry of an organic charge transfer complex (CT complex) between pyrazole (donor) and chloranilic acid (acceptor) has been explored in ethanol at room temperature. The synthesized complex has been characterized by various techniques such as FTIR, NMR, Single crystal X-ray diffraction and UV-visible spectroscopy. These techniques indicate that the cation and anion are joined together by the weak hydrogen bonding. This molecular framework is a result of inter N+-H⋯O- bonding between donor and acceptor moieties. The elemental analysis and FTIR spectrum of semi-crystal complex along with Job's plot indicate the formation of 2: 1 HBCT-complex. The bioorganic chemistry of the present CT complex is established well toward antimicrobial screening and DNA binding capabilities. Antimicrobial activity was screened for gram positive and gram negative bacteria and various fungi. Molecular docking shows that the CT complex binds perfectly with the B-DNA and reveals free energy of binding (FEB) value of -198.4 kcal mol-1. TD-DFT calculations using basis set B3LYP/6-311G** give theoretical confirmation along with HOMO (-3.9421 eV) â†’ LUMO (-2.4903 eV) electronic energy gap (ΔE) to be 1.4521 eV. Theoretical analysis corroborates well the biological properties.