Heteroleptic cobalt(II) coordination compounds fabricated from the CoX2 (X=NO3-, Cl-) salts, benzoic acid and polypyridines (1,10-phenanthroline, 2,2′-bipyridine)


Panova E., Voronina J. K., Azizova A. N., Tutar Ö. F., Mahmoudi G., Safin D. A.

JOURNAL OF MOLECULAR STRUCTURE, vol.1352, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 1352
  • Publication Date: 2026
  • Doi Number: 10.1016/j.molstruc.2025.144040
  • Journal Name: JOURNAL OF MOLECULAR STRUCTURE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
  • Azerbaijan State University of Economics (UNEC) Affiliated: No

Abstract

Motivated by the previous studies reported by Benali-Cherif et al. "Comprehensive study of a novel cobalt(II) complex: Synthesis, X-ray crystal structure, Hirshfeld surface analysis, computational quantum investigations, and molecular docking insights" (Polyhedron 271 (2025) 117,445), we synthesized heteroleptic cobalt(II)-based complexes from CoX2 & sdot;6H2O (X = NO3-, Cl-), benzoic acid (bzH) and 1,10-phenathroline (phen) or 2,2 '-bipyridine (bpy). It was established that using Co(NO3)2 & sdot;6H2O and phen yielded complex [Co(phen)2bz]NO3 & sdot;2bzH (1). Using CoCl2 & sdot;6H2O and phen allowed to produce complex [Co(phen)bz2(H2O)] (2), while using CoX2 & sdot;6H2O (X = NO3-, Cl-) and bpy produced the same complex [Co(bpy)bz2] (X = NO3-, 3-I; Cl-, 3-II) regardless of the nature of the anion in the parent cobalt salt. Elemental analysis and powder X-ray diffraction confirmed the composition and purity of the isolated complexes. Diffuse reflectance and UV-Vis spectroscopy revealed optical properties of complexes 1-3, with the bands assigned to intraligand, MLCT and d-d transitions. Bidentate coordination of the bz anions was established in the crystal structures of 1 and 3, while monodentate coordination of the bz anions was established in the crystal structure of 2. Structures of 1 and 2 were stabilized by O-H & sdot;& sdot;& sdot;O hydrogen bonds and pi & sdot;& sdot;& sdot;pi interactions. The RDG and combined QTAIM/NCI analyses supported the described bonding interactions. Molecular docking predicted similar potential inhibition against a Klebsiella pneumoniae protein for all complexes, with favorable ligand efficiency scores and distinct interaction profiles stabilizing the complexes.