‘Soft–soft’ halogen–halogen interactions in solid ion pairs of solvent-free Pri3PCl2 and CH2Cl2-solvated Pri3PBr2: structural features of chloro- and bromo-triisopropylphosphonium salts
Abstract
An X-ray crystallographic study of solvent-free Pri3PCl2 and dichloromethane-solvated Pri3PBr2 reveals that both halogenophosphonium halides exist as monomeric ion pairs Pri3P+–X···X–; elongations of P–Cl and P–Br bonds are associated with Cl···Cl and Br···Br interactions.