The coordination of a multidentate N_xO_y-donor (x and y ≤ 2) oxazolidine-based ligand with Cd(II) and Hg(II); Structural, spectral, and theoretical studies

Abstract

Two binuclear complexes, fac-[Cd₂(AEPC)₂(μ-Cl)₂Cl₂] (1) and [Hg₂(AEPC)₂(μ-Cl)₂Cl₂] (2), of 2-(2-(pyridin-2-yl)oxazolidin-3-yl)ethanol (AEPC) were prepared and identified by elemental analysis, FT-IR, ¹H NMR spectroscopies, and single-crystal X-ray diffraction. All coordination modes of 2-(pyridin-2-yl)oxazolidine derivatives were studied by analysis of the Cambridge Structural Database (CSD) for determination of coordination behaviors of the AEPC ligand with metals. In the crystal structure of 1, the cadmium ion has a distorted octahedral geometry and CdN₂OCl₃ environment in which each ligand acts as an NN′O-donor. In the crystal structure of 2, the AEPC acts as NN′-donor toward the mercury ion to form a square-pyramidal geometry with three chloride ions. Each complex contains four chiral centers with a center of inversion and C_i symmetry. In the crystal networks of the complexes, the alcohol groups of the ligands participate in hydrogen bonding and form (28) and (44) hydrogen bond motifs (observed for 1). In addition to the hydrogen bonds, the crystal network is stabilized by π–π stacking interactions between pyridine rings of the AEPC ligands of adjacent complexes. The thermodynamic stability of the isolated complexes and their charge distribution patterns were studied by DFT and NBO analysis.

Keywords:

• Oxazolidine
• cadmium
• mercury
• DFT calculations
• binuclear complex
• chiral center
• fac isomer

Notes

1. For comparing the energy level of mononuclear with binuclear, its energy value should be multiplied by two.