Supramolecular coordination polymers, obtained from multidentate N′-benzoylpyrazine-2-carbohydrazonamide and a variety of salts PbX2 (X = Cl−, NO3−, NO2−, SCN−), derived from tetrel and other noncovalent bonds
Year: 2025
Type: article
Abstract: Four lead(II) complexes, [Pb( HL )Cl₂] ( 1 ), [Pb(HL)₂(NO₃)₂] ( 2 ), [PbL(NO₂)] ( 3 ), and [PbL(NCS)(H₂O)] ∙ H₂O ( 4 ∙H₂O), were synthesized from PbX₂ salts and the ligand N′-benzoylpyrazine-2-carbohydrazonamide (HL). Spectroscopic characterization confirmed that complexes 1 and 2 contain the neutral ligand (HL), while 3 and 4 ∙H₂O feature its deprotonated form (L). In all structures, the Pb 2+ center is N,N′,O-chelated by the ligand. Bond length analysis revealed the longest Pb N/O bonds in 2 due to coordination of two neutral HL ligands, whereas the deprotonated L − in 3 and 4 ∙H₂O resulted in shorter Pb N imine and Pb O carbonyl bonds. Secondary Pb⋯X tetrel bonds (X = Cl, N, O, S) form in complexes 1 , 3 , and 4 ∙H₂O due to coordination sphere gaps, leading to supramolecular 1D chains ( 1 , 4 ∙H₂O) or a 2D sheet ( 3 ). These assemblies are further stabilized by extensive hydrogen bonding and π⋯π stacking interactions. The nature of the tetrel bonds was investigated using MEP surface analysis, dimerization energy calculations, and quantum chemical tools (QTAIM, NCIplot). Electron localization function (ELF) and Laplacian maps differentiated tetrel bonds from primary coordination bonds, and the energy contributions of coexisting tetrel and hydrogen bonds were quantified. • Four new Pb(II) coordination polymers were synthesized and studied. • Ligand deprotonation is induced by specific anions. • Anisotropic Pb centers form stabilizing tetrel bonds. • Theoretical analysis distinguishes bond types and quantifies forces.
Authors: Ghodrat Mahmoudi, Isabel Garcia-Santos, Alfonso Castiñeiras, Atash V. Gurbanov, Ömer Faruk Tutar, Elizaveta V. Panova, Rosa M. Gomila, Antonio Frontera, Damir A. Safin
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,550
OpenAlex ID: W4417537305