Molecular structure and DFT investigations on new cobalt(II) chloride complex with superbase guanidine type ligand

Abstract

The new [Co(btmgn)Cl 2 ] complex and the 1,8-bis(tetramethylguanidino)naphthalene (btmgn) ligand were synthesized and characterized. The X-ray single crystal investigation showed distorted tetrahedral geometry around the Co(II) ion. The geometry of the btmgn and [Co(btmgn)Cl 2 ] complex was optimized using the B3LYP/6-311G(d,p) method. The calculated geometric parameters at the optimized structure of the [Co(btmgn)Cl 2 ] complex showed good agreement with our reported X-ray structure. The two tetramethylguanidino groups are in a cis-type position to the naphthalene ring plane both in the free and coordinated btmgn. The large red shift of the υ C=N mode upon coordination indicates the strong ligand-metal interactions. The calculated natural charges using natural bond orbital (NBO) analysis at the two coordinated Cl-atoms are not equivalent. Also the two LP(4)Cl→LP*(3)Co intramolecular charge transfer interaction energies (E (2)) are 29.00 and 39.17 kcal/mol, respectively. The two Co-Cl bonds are not equivalent where the longer Co-Cl bond has more electronegative chlorine atom than the shorter one. Molecular electrostatic potential (MEP) study of the btmgn ligand showed that the N4 and N7 atoms are the most reactive nucleophilic centers for the coordination with the Co 2+ ion. The [Co(btmgn)Cl 2 ] complex has higher polarizability (α 0), first hyperpolarizability (β 0) and lower energy gap (E) than the free ligand. The TD-DFT calculations predicted the transition bands at 337.2 nm (f=0.2299, H→L) and 342.6 nm (f=0.1465, H-2/H→L) for the btmgn and [Co(btmgn)Cl 2 ], respectively.

Syntheses, Crystal Structure and Theoretical Properties of Schiff Bases Obtained from Isoniazid and Pyridine‐2‐, 3‐, 4‐Carboxaldehyde and Their Zinc(II) Complexes

“…The contributions of the remaining contacts are smaller than 2.5 % to the HSs with the low densities of points. Although Zn⋅⋅⋅H and Zn…Cl interactions are negligible, they still contribute to the structure of zinc complexes [50,51] …”

“…The overall two-dimensional fingerprint plots, Figures 6-10 (a-e) a, and those delineated into H [49] are illustrated in Figures 6b-j Although Zn•••H and Zn…Cl interactions are negligible, they still contribute to the structure of zinc complexes. [50,51] The nearest neighbor coordination environment of a molecule can be determined from the color patches on the HS based on how close to other molecules they are. The Hirshfeld surface representations with the function d norm plotted onto the surfaces are shown for the H…”

Highly active heterogeneous hydrogenation catalysts prepared from cobalt complexes and rice husk waste

“…The depicted structure is based on previously published materials. [44][45][46][47] Fig. 2 Carbon bonds in the different stages of catalyst processing, measured by XPS.…”

“…Subsequently, the material was washed with water and added to an ethanolic solution of an in situ prepared cobalt complex bearing nitrogen-donor ligands (Scheme 2). [44][45][46][47] After removing the solvent in vacuo, the dried material was pyrolyzed at 600 °C under an inert atmosphere. Finally, the resulting ashes were etched with a base.…”

Synthesis, X-ray structure and theoretical investigation of 2-(2’-quinolyl)benzimidazole metal complexes

“…Nitrogen-based ligands are extensively studied as complexes with many metal ions such as cobalt and manganese. 1,2 Coordination complexes based on nitrogen donor chelate ligands and cobalt or manganese ions, having a number of available oxidation states, have attracted great attention because of their potential applications in various fields of human interest such as antitumor, 3,4 antiviral, 5,6 antifungal and antibacterial 7,8 and antioxidant 9,10 drugs. In addition to the biological importance, diverse catalytic 11,12 and magnetic properties 13,14 of such compounds have been explored.…”