Spectral, thermal and DFT studies of novel nickel(II) complexes of 2-benzoylpyridine-N4-methyl-3- thiosemicarbazone: Crystal structure of a square planar azido-nickel(II) complex

Synthesis of Zn(ii) coordination complexes, their molecular design and docking with SARS-CoV-2 RBD protein and Omicron spike protein

“…The distortion of the geometrical environment was confirmed by the geometrical index τ 5 . 70 This parameter measures the distortion between a perfect trigonal bipyramidal ( τ 5 = 1) and a perfect square pyramidal geometry ( τ 5 = 0) with the formula: τ 5 = β − α /60, in where α and β are the two largest angles around the central metal in the complex. The τ 5 value was 0.564 for zinc centre and this value confirmed the coordination geometry of the Zn( ii ) complex [Zn(L)(en)]ClO 4 ( 1 ) as a distorted square pyramidal geometry around the metal centre.…”

“…The τ 5 value was 0.564 for zinc centre and this value confirmed the coordination geometry of the Zn( ii ) complex [Zn(L)(en)]ClO 4 ( 1 ) as a distorted square pyramidal geometry around the metal centre. 70 In the Zn( ii ) complex [Zn(L)(en)]ClO 4 ( 1 ), the equatorial positions of the geometry were satisfied by three donor atoms of the Schiff base (L) ligand and one nitrogen atom N(5) of the ethylenediamine (en) moiety while the remaining nitrogen atom N(6) of the ethylenediamine (en) was in the axial position. One of the reasons for the deviation from an ideal stereochemistry was the restricted bite angle imposed by both the Schiff base (L) and ethylenediamine ligands.…”

“…The bite angle around the Zn( ii ) was 77.53(8)°, which may be considered normal when compared with an average value of 77° cited in the literature. 70,71 The bond angles of N(2)–Zn(1)–O(1), N(5)–Zn(1)–O(1), and O(1)–Zn(1)–N(1) as 75.47(7)°, 97.42(8)°, and 152.86(8)°, respectively, indicate a slight tilting of the apical Zn(1)–N(2) bond in the direction of the N(1)–Zn(1) bond and away from N(5)–Zn(1) bond. The Zn–O and Zn–N bond distances were in the usual range as reported in the literature.…”

mer-Bis(quinoline-2-carboxaldehyde 4-ethylthiosemicarbazonato)nickel(II) methanol 0.33-solvate 0.67-hydrate

“…Ni II complexes having sulfur donors have been studied, receiving considerable attention due to the identification of a sulfur-rich coordination environment in biologically relevant nickel ompounds, such as the active sites of certain ureases, hydrogenases, as well as dehydrogenases, that may play a role in the supposed mutagenicity of nickel compounds (Latheef et al, 2021). The coordination chemistry of nickel is thus of interest with respect to its important roles in biological systems (Jayakumar et al, 2022;Sankar & Sharmila, 2023). This is due to the ability of nickel to adopt different coordination environments, such as tetrahedral, square planar and octahedral.…”

“…This is due to the ability of nickel to adopt different coordination environments, such as tetrahedral, square planar and octahedral. The nickel ion can also bind to soft and hard donor ligands, which allows its coordination chemistry to encompass a variety of coordination environments, coordination numbers and oxidation states (Jayakumar et al, 2022).…”