The 'super acid' BF3H2O stabilized by 1,4-dioxane: new preparative aspects and the crystal structure of BF3H2O·C4H8O2.

ABSTRACT: Highly Brønsted-acidic boron trifluoride monohydrate, a widely used 'super acid-catalyst', is a colourless fuming liquid that releases BF3 at room temperature. Com-pared to the liquid com-ponents, i.e. boron trifluoride monohydrate and 1,4-dioxane, their 1:1 adduct, BF3H2O·C4H8O2, is a solid with pronounced thermal stability (m.p. 401-403 K). The crystal structure of the long-time-stable easy-to-handle and weighable com-pound is reported along with new preparative aspects and the results of 1H, 11B, 13C and 19F spectroscopic investigations, particularly documenting its high Brønsted acidity in aceto-nitrile solution. The remarkable stability of solid BF3H2O·C4H8O2 is attributed to the chain structure established by O-H⋯O hydrogen bonds of exceptional strength {O2⋯H1-O1 [O⋯O = 2.534 (3) Å]

SUBMITTER: Barthen P 

PROVIDER: S-EPMC6829742 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature