Synthesis, structural characterization, and theoretical analysis of novel zinc(ii) schiff base complexes with halogen and hydrogen bonding interactions.

In this article, we present the synthesis and characterization of three zinc(ii) complexes, [Zn ^II (HL ¹ ) ₂ ] (1), [Zn ^II (HL ² ) ₂ ]·2H ₂ O (2) and [Zn ^II (HL ³ ) ₂ ] (3), with three tridentate Schiff base ligands, H ₂ L ¹ , H ₂ L ² , and H ₂ L ³ . The structures of the complexes were confirmed by single-crystal X-ray diffraction analysis. DFT calculations were performed to gain insights into the self-assembly of the complexes in their solid-state structures. Complex 1 exhibits dual halogen-bonding interactions (Br⋯Br and Br⋯O) in its solid-state structure, which have been thoroughly investigated through molecular electrostatic potential (MEP) surface calculations, alongside QTAIM and NCIPlot analyses. Furthermore, complex 2 features a fascinating hydrogen-bonding network involving lattice water molecules, which serves to link the [Zn ^II (HL ² ) ₂ ] units into a one-dimensional supramolecular polymer. This network has been meticulously examined using QTAIM and NCIplot analyses, allowing for an estimation of the hydrogen bond strengths. The significance of H-bonds and CH⋯π interactions in complex 3 was investigated, as these interactions are crucial for the formation of infinite 1D chains in the solid state.
Competing Interests: There are no conflicts to declare.
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