Research Information System
JOURNAL OF MOLECULAR STRUCTURE, vol.1365, 2026 (SCI-Expanded, Scopus)
Combining aqueous Pb(OAc)2 with a methanolic solution of the ligand N'-benzoylpyrazine-2-carbohydrazonamide (HL) yielded two distinct lead(II) complexes. The minor product [PbL(OAc)]& sdot;H2O (1 & sdot;H2O) was obtained in 8% yield as orange plates, while the major product [Pb2L2(OAc)2]n & sdot;2nMeOH (2 & sdot;2nMeOH) was obtained in 40% yield as orange needles. Both complexes were characterized by elemental analysis, FTIR and 1H NMR spectroscopy, which confirmed ligand deprotonation. X-ray diffraction revealed distinct architectures: 1 & sdot;H2O features a monodentate acetate and a PbN3O3 coordination core, forming supramolecular dimers via Pb & sdot;& sdot;& sdot;N tetrel bonds. These dimers assemble into 1D chains through hydrogen bonds and it & sdot;& sdot;& sdot;it interactions. In contrast, 2 & sdot;2nMeOH forms a 1D coordination polymer with bidentate acetates and PbN5O4 coordination cores, which extend into a 2D sheet via an extensive network of tetrel bonds, hydrogen bonds and it & sdot;& sdot;& sdot;it interactions. Furthermore, we employed DFT-based calculations to investigate the nature of the non-covalent interactions governing the crystal packing. The MEP surfaces, along with the QTAIM and NCI plot analyses, were used to characterize the key interactions, including tetrel bonds and electrostatically enhanced it & sdot;& sdot;& sdot;it stacking between the coordinated pyrazine and phenyl rings, as well as secondary hydrogen bonds that complement primary interactions in the selected dimers. The analysis revealed that the Pb & sdot;& sdot;& sdot;N interactions in 2, which link the monomeric units into a coordination polymer, exhibit characteristics of a strong tetrel bond. This finding allows for the reinterpretation of compound 2 as a supramolecular polymer. We also used 2D plots of the ELF, RDG and Laplacian of the electron density (del 2 rho) to further characterize selected Pb & sdot;& sdot;& sdot;N tetrel bonds as non-covalent interactions involving sigma-holes in 1.