Complexes of BiCl3with hydrazone derived ligands: a Möbius-like discrete metal chelateversusa salt-like porous polymeric structure

In this work we have synthesized and characterized a new helical complex of BiCl3, namely[Bi(LI)Cl3], fabricated with an extremely bulky ligand, 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane (LI). The same reaction of BiCl3withN′-(4-hydroxybenzylidene)isonicotinohydrazide (HLII) has allowed us to obtain a salt-like porous polymeric structure([H2LII]2[BiCl5]·EtOH)n. As evidenced from the single crystal X-ray analysis data, complex[Bi(LI)Cl3]is a Möbius-like discrete metal chelate, where the BiIIIatom is seven-coordinated in a distorted pentagonal bipyramidal N4Cl3geometry and the organic ligandLIadopts a helical twist conformation. The structure of compound([H2LII]2[BiCl5]·EtOH)ncomprises monoprotonated non-coordinated organic molecules [H2LII]+counterbalanced by a [BiCl5]2−anionic fragment, which, in turn, forms a 1D zig-zag polymeric chain. The organic molecules are arranged in a centrosymmetric fashion yielding a hydrogen bonded tetramer with a rectangular cavity of dimensions 7.55 × 9.02 Å. The tetramers are stacked through weak intermolecular interactions, yielding 1D infinite channels. Thus, complex([H2LII]2[BiCl5]·EtOH)nwas found to be a porous organic-inorganic hybrid compound. By using DFT calculations we have analyzed and rationalized the molecular electrostatic potential (MEP) surfaces and, through the quantum theory of the “atoms-in-molecules” (QTAIM) computational tool, the hydrogen bonding interactions observed in the solid state of both crystal structures, focusing on the competition between O-H⋯O and N-H⋯O hydrogen bonds in([H2LII]2[BiCl5]·EtOH)n. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2020.