title: Chemistry and structures of hexakis(halogenomethyl)-, hexakis(azidomethyl)-, and hexakis(nitratomethyl)disiloxanes.
abstract: An investigation of the structures and chemistry of substituted hexamethyl disiloxanes ((XCH2)3Si)2O; X=F, Cl, Br, I, N3 , and ONO2) is reported. New synthetic routes to the precursor hexakis(chloromethyl)disiloxane are presented. The products with X=Cl, Br, I, and N3 were characterized by NMR, IR, and Raman spectroscopy. In addition, the single-crystal structures of the products with X=Cl, Br, and I are discussed in detail. The compounds with X=F and ONO2 were not obtained in their pure form; instead investigations of the decomposition products revealed their conversion into intermediates. Theoretical calculations of the gas-phase structures at the B3LYP/cc-pVDZ, B3LYP/3-21G, MP2/6-31G*, and MP2/3-21G levels of theory are used to explain the chemical and physical behavior of the compounds with X=Cl, Br, I, N3, and ONO2. A new decomposition pathway of hexakis(nitratomethyl)disiloxane is presented and is used to explain their remarkable instability. The energetic properties and values of the nitrate and azide derivatives were calculated at the CBS-4M level of theory by using the improved EXPLO5 computer code version 6.01.
authors.affiliation: Chemistry Department, Ludwig-Maximilian-University Munich, Butenandtstr. 5-13(D), 81377 Munich, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Ascherl
authors.forename: Camilla
authors.initials: C
authors.lastname: Evangelisti
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Klapötke
authors.forename: Burkhard
authors.initials: B
authors.lastname: Krumm
authors.forename: Julia
authors.initials: J
authors.lastname: Nafe
authors.forename: Anian
authors.initials: A
authors.lastname: Nieder
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rest
authors.forename: Christian
authors.initials: C
authors.lastname: Schütz
authors.forename: Muhamed
authors.initials: M
authors.lastname: Suceska
authors.forename: Matthias
authors.initials: M
authors.lastname: Trunk
keywords: NMR spectroscopy; azides; energetic materials; halides; silanes