title: Polynitroethyl- and fluorodinitroethyl substituted boron esters.
abstract: The reaction of boron oxide with various nitro-substituted ethanols (2-nitroethanol, 2-fluoro-2,2-dinitroethanol, 2,2,2-trinitroethanol) furnished the corresponding nitroethyl borates B(OCH2CH2NO2)3 (1), B(OCH2CF(NO2)2)3 (2), and B(OCH2C(NO2)3)3 (3). Fluorination of the anion [(NO2)2CCH2OH](-) (4) resulted in 2-fluoro-2,2-dinitroethanol (5), a precursor for 2, and was thoroughly characterized. An interesting condensation was observed with the anion 4 to form the unusual dianion [(NO2)2CCH2C(NO2)2](2-) (6). All compounds were fully characterized by multinuclear NMR spectroscopy, vibrational spectroscopy (IR, Raman), mass spectrometry and elemental analysis. The chemical, physical and energetic properties of 1-3 and 5 are reported, as well as quantum chemical calculations at the CBS-4M level of theory to predict the enthalpies and energies of formation. X-ray diffraction studies were performed, and the crystal structures for compounds 1-6 were determined and discussed thoroughly. The boron esters 1-3 are of interest as possible candidates for smoke-free, green colorants in pyrotechnic applications, and in case of 2 and 3 also as promising high energy oxidizers.
authors.affiliation: Department of Chemistry, Ludwig-Maximilian University of Munich, Butenandtstr. 5-13 (D), 81377 Munich (Germany), Fax: (+49) 89-2180-77492. tmk@cup.uni-muenchen.de.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Klapötke
authors.forename: Burkhard
authors.initials: B
authors.lastname: Krumm
authors.forename: Richard
authors.initials: R
authors.lastname: Moll
keywords: X‐ray diffraction; boron; fluorination; multinuclear NMR spectroscopy; polynitro