Pb⋯N interactions and π-stacking in lead(II) bis(hydrazone) compounds

2,6-Diacetylpyridine-bis(benzoylhydrazone), H2LPh, reacts with Pb(OAc)2·3H2O and NEt3 as a supporting base forming a polymeric solid of the composition [Pb(LPh)]n. A reaction with pyridine results in cleavage of the polymer and formation of the dimeric, crystalline compound [Pb(py)(LPh)]2.Similar reactions with PbX2 salts (X = Cl, Br, I) also give almost insoluble solids of the tentative composition [Pb(H2LPh)X2]n. After ongoing reactions with DMSO, single deprotonation of the organic ligand and the formation of pseudo-dimeric [Pb(HLPh)X]2 complexes was observed. Depending on the presence of solvent molecules they form different supramolecular aggregates by π–π interactions.The use of Pb(NO3)2 results in a dimeric structure with relatively short Pb–O bonds of 2.442(2) Å between the monomeric sub-units. The formed dimers aggregate to a polymeric assembly by hydrogen bonds.The products were studied by spectroscopic methods and X-ray diffraction.

Graphical abstract2,6-Diacetylpyridine-bis(benzoylhydrazone), H2LPh, reacts with different lead(II) salts forming dimeric and pseudo-dimeric structures, which are organized to supramolecular assemblies by π-stacking or hydrogen bonds.Figure optionsDownload full-size imageDownload as PowerPoint slide