An unprecedented non-classical polyinterhalogen anion made of [I2Cl](-) and I-2 at the 2-(p-tolyl)selenopheno[2,3-b]pyridinium cation template

The reactivity between 2-(p-tolyl)selenopheno[2,3-b]pyridine (L) and ICl in MeCN is presented. Single crystal structure analysis revealed the formation of two distinct crystalline materials both featuring the protonated 2-(p-tolyl)selenopheno[2,3-b]pyridinium cation [HL](+). Colourless crystals were identified as the dihydrate salt [HL]Cl & BULL;2H(2)O (1), and dark-red crystals as compound {[HL](+)[I2Cl](-)}(3)& BULL;1/2I(2) (2) that features the peculiar presence of the rare non-classical [I2Cl](-) interhalide. Halogen Bonds (XBs) between the cocrystallized I-2 molecule and [I2Cl](-) anions led to the novel overall discrete [I10Cl4]H4--shaped polyinterhalide formation, which is stabilized through hydrogen bonds (HBs) with the templating [HL](+) cations. The experimental observations are supported by extensive theoretical calculations at the DFT level that were employed to study the role played by non-covalent interactions in the formation of the presented unique polyinterhalide.

Automated summary

This article presents the reactivity between 2-(p-tolyl)selenopheno[2,3-b]pyridine (L) and ICl in MeCN, revealing the formation of two distinct crystalline materials, one of which features the rare [I2Cl](-) interhalide.