Definitive crystal structures of ortho-, meta- and para-carboranes: supramolecular structures directed solely by C–H⋯O hydrogen bonding to hmpa (hmpa = hexamethylphosphoramide)

Abstract

Cocrystallisation of ortho-meta- and para-carboranes with hmpa (hexamethylphosphoramide) results in the isolation of 1 : 1 carborane:hmpa adducts which provide the first definitive X-ray structures of the unsubstituted carboranes as part of three very different C–H⋯O hydrogen-bonded supramolecular structures.