title: Understanding the solubility of triamino-trinitrobenzene in hydrous tetramethylammonium fluoride: a first principles molecular dynamics simulation study.
abstract: With the aim to understand the relatively high solubility of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), an important energetic material with a high degree of inter- and intra-molecular hydrogen bonding, in fluoride anion containing ionic liquids (ILs), first principles molecular dynamics simulations in the isobaric-isothermal ensemble were carried out for a system using hydrous tetramethylammonium fluoride as the prototypical solvent. Simulations initiated from both molecular TATB and its Meisenheimer complex (i.e., a σ-complex of the fluoride and the electrophilic ring of TATB) yield a Zundel-type complex where a proton is shared between an amino group and an F(-) ion, whereas the Meisenheimer complex is found to be only transiently stable. An analysis of the electronic structure probing the Wannier function centers supports the finding of a proton-sharing complex with a three-center four-electron like bond. The Zundel-type complex also yields an electronic absorption spectrum consistent with the experimentally observed color change. This study provides evidence that the remarkable solubility of otherwise hard-to-dissolve molecular crystals in ILs can be aided by chemical modification of the solute.
authors.affiliation: Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA.
authors.forename: Bhabani S
authors.initials: BS
authors.lastname: Mallik
authors.forename: I-F William
authors.initials: IF
authors.lastname: Kuo
authors.forename: Laurence E
authors.initials: LE
authors.lastname: Fried
authors.forename: J Ilja
authors.initials: JI
authors.lastname: Siepmann