Crystal structure of bis­(3-carb­oxy-1-methyl­pyrid­inium) octa­bromide

Abstract

The structure of the title compound is composed of rare Z-shaped octa­bromide anions embedded within N-methyl­nicotinic acid cations.

The crystal structure of the title salt, bis­(3-carb­oxy-1-methyl­pyridinium) octa­bromide, 2C₇H₈NO₂ ⁺·Br₈ ²⁻, consists of 3-carb­oxy-1-methyl­pyridinium (N-methyl­nicotinic acid) cations, which are stacked between relatively rare [Br₈]^2– anions. The polybromide [Br₈]^2– anion has point group symmetry

and can be described as being composed of two [Br₃]⁻ anions connected with a Br₂ mol­ecule in a Z-shaped manner. Contacts between neighboring octa­bromide anions ensure the creation of pseudo-polymeric chains propagating along [111]. The organic cations are located between anionic chains and are connected to each other through O—H⋯O hydrogen bonds and to the [Br₈]^2– anions through π⋯Br inter­actions that induce the creation of a supra­molecular tri-periodic network. In addition, the presence of weak C—H⋯Br contacts leads to the creation of layers, which align parallel to (11

).