Iodine-Rich\nSupramolecular Complexes of Chlorobismuthates(III):\nUnusual Lone Pair Activity and Features of Halogen Bonding in Crystals

The first chrorobismuthate(III) supramolecular hybrids\nwith halogen-bond-linked\nI<sub>2</sub>, (Py(CH<sub>2</sub>)<sub>2</sub>Py){[BiCl<sub>5</sub>](I<sub>2</sub>)} (<b>1</b>) and (Py(CH<sub>2</sub>)<sub>3</sub>Py){[BiCl<sub>5</sub>](I<sub>2</sub>)<sub>0.5</sub>} (<b>2</b>), were synthesized via the reaction between Bi<sub>2</sub>O<sub>3</sub>, I<sub>2</sub>, and salts of the corresponding cations in\nHCl. The compounds featured one- and two-dimensional (2D) supramolecular\nmotifs built by I···Cl contacts; in the case of <b>1</b>, Bi(III) is pentacoordinated due to the lone pair activity,\nwhich also interacted with I<sub>2</sub> pi-orbitals, as confirmed\nby density functional theory (DFT) calculations. Both complexes exhibited\nmoderate thermal stabilities and relatively narrow optical band gaps.