Synthesis, characterization, X-ray structural analysis, DFT and BSA binding study of a Zn(II) complex, [Zn(II)Cl₂(nia)₂].2nia

Abstract

A Zn(II) complex with two nicotinamide (nia) ligands, two chloride ions, and two co-crystallized nicotinamide molecules, [ZnCl₂(nia)₂].2nia, was synthesized and characterized on the basis of elemental analysis, spectroscopic techniques (UV-vis, FT-IR, ¹H and ¹³C NMR), conductivity measurements, DFT and single-crystal X-ray crystallography. The complex crystallized in orthorhombic crystal system with pccn space group and cell dimensions: a = 27.1852(2), b = 7.6705(4), c = 12.7502(8) Å and α = β = γ = 90°. Single-crystal structural analysis revealed the presence of a neutral complex having tetrahedral geometry. In this complex, Zn(II) is coordinated to two chloride and two nicotinamide ligands in the coordination sphere and two nicotinamide molecules are co-crystallized. Hydrogen bonding interactions (N-H…O, C-H…O, N-H…N, C-H…Cl) along with π…π bonding interactions (between the coordinated nicotinamide and free nicotinamide moiety) stabilize the crystal lattice. The DFT studies consolidated the experimental findings and provided deeper insight into vibrational spectra, excitation spectra and hydrogen bonding interactions between nicotinamide molecules. The interactions and binding parameters of this complex with bovine serum albumin (BSA) have been probed through absorption and fluorescence spectroscopy which revealed the presence of static quenching mechanism and good binding propensity of the Zn complex.

Graphical Abstract

Keywords:

• Zinc(II)
• Nicotinamide
• Chloride
• Spectroscopy
• X-ray
• DFT

Acknowlegement

The authors are thankful to Prof. Dhiraj Sud (Head Chemistry Department, SLIET Longowal) for her support. Author PK thanks the Director, NIT Uttarakhand and TEQIP-III for support in this work.

Disclosure statement

No potential conflict of interest was reported by the authors.