title: Pentaborate(1-) salts templated by substituted pyrrolidinium cations: synthesis, structural characterization, and modelling of solid-state H-bond interactions by DFT calculations.
abstract: The synthesis and characterization of a series of pentaborate(1-) salts of substituted pyrrolidinium cations [C4H8NH2][B5O6(OH)4] (), [C4H8NMe2][B5O6(OH)4] () [C4H8NMeH][B5O6(OH)4] (), [(2-CH2OH)C4H7NH2][B5O6(OH)4] () is reported. All compounds were characterized by single-crystal XRD studies with (1/2CH3COCH3) and (1/2H2O) solvated. TGA/DSC analysis of the pentaborates showed that they thermally decomposed in air at 800 °C to 2.5 B2O3, in a 2 step process involving dehydration (<250 °C) and oxidative decomposition (250-600 °C). BET analysis of materials derived thermally from the pentaborates and had internal porosities of <1 m(2) g(-1), indicating they were non-porous. All compounds show extensive supramolecular H-bonded anionic lattices. H-bond interactions are described in detail and motifs found in these and in other pentaborate structures have been examined and modelled by DFT calculations. These calculations confirm that H-bonds interactions in pentaborates are moderately strong (ca. -10 to -21 kJ mol(-1)) and are likely to dominate the energetics of their templated syntheses.
authors.affiliation: School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, UK. m.a.beckett@bangor.ac.uk.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Beckett
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Coles
authors.forename: R Andrew
authors.initials: RA
authors.lastname: Davies
authors.forename: Peter N
authors.initials: PN
authors.lastname: Horton
authors.forename: Charlotte L
authors.initials: CL
authors.lastname: Jones