Logo
DeutschClear Cookie - decide language by browser settings
Scherr, Matthias (2008): Beiträge zur Chemie der energetischen Chalkogen-Verbindungen. Dissertation, LMU München: Faculty of Chemistry and Pharmacy
[img]
Preview
PDF
Matthias_Scherr.pdf

8Mb

Abstract

This thesis focuses on the preparation of new chalcogen and silver compounds, which are in part extremely moisture sensitive or energetic materials. The reaction of SeF4 with Me3SiN3 at low temperatures resulted in the formation of the first binary selenium(iv) azide Se(N3)4. The reactions of [SeF5]– and [SeF6]2– with Me3SiN3 furnished the corresponding polyazidoselenites [Se(N3)5]– and [Se(N3)6]2–. All materials are extremely temperature sensitive. The preparation of the binary selenium(iv) cyanide Se(CN)4 was attempted by the reaction of SeF4 with Me3SiCN at low temperatures. However, selenium tetracyanide could not be detected by NMR spectroscopy; instead, the decomposition product Se(CN)2 was isolated and its crystal structure was redetermined. The binary selenium(iv) fluorides [SeF5]– and [SeF6]2–, used as starting materials for the syntheses of the binary selenium(iv) azide compounds, have been characterized with the help of multinuclear NMR spectroscopy and compared with the literature. In addition the crystal structure of the unknown selenium(iv) oxofluoride anion [SeOF3]– was obtained and compared with the known structures of [SOF3]– and [TeOF3]– . The reaction of organoselanes and -diselanes (R2Se and (RSe)2) with XeF2 furnished the corresponding organoselenium(iv) difluorides R2SeF2 (R = Me, Et, i-Pr, Ph, Mes (= 2, 4, 6-(Me)3C6H2), Tipp (= 2, 4, 6-(i-Pr)3C6H2), 2 -Me2NCH2C6H4), and trifluorides R0SeF3 (R0 = Me, i-Pr, Ph, Mes, Tipp, Mes* (= 2, 4, 6-(t-Bu)3C6H2), 2-Me2NCH2C6H4), respectively. In addition to characterization by multinuclear NMR spectroscopy, the first molecular structure of an organoselenium(iv) difluoride as well as the molecular structures of subsequent decomposition products have been determined. The substitution of fluorine atoms with Me3SiN3 leads to the corresponding organoselenium(iv) diazides R2Se(N3)2 (R = Me, Et, i-Pr, Ph, Mes, 2-Me2NCH2C6H4) and triazides R0Se(N3)3 (R0 = Me, i-Pr, Ph, Mes, Tipp, Mes*, 2-Me2NCH2C6H4), respectively. The organoselenium azides are extremely temperature-sensitive materials and can only be handled at low temperatures. The reaction of dibenzoselenophene (biphenSe) with halogenides or halogenidedonating compounds, respectively, furnished the corresponding organoselenium(iv) halogenides biphenSeF2, biphenSeCl2, biphenSeBr2, as well as the charge-transfer-adduct biphenSe·I2. Besides their NMR spectroscopic characterization, the molecular structures of the dichloride, dibromide, and the iodine-adduct could be determined. In analogy the reaction of dibenzo[1,2]diselenine with three equivalents of halogenide or halogenidedonating compound was examined. The syntheses of the triorganochalcogenonium dinitramide salts [Ph3Te][N(NO2)2], [Me3Te][N(NO2)2], [Ph3Se][N(NO2)2], [Me3Se][N(NO2)2], [Ph3S][N(NO2)2], and [Me3S][N(NO2)2], their characterization by multinuclear NMR spectroscopy, vibrational spectra, and single crystal structures were described. The syntheses of the compounds were achieved using [Ag(py)2][N(NO2)2] and [Ag(NCCH3)][N(NO2)2] as dinitramide transfer reagents. Besides those ionic salts, the preparation of the first covalent tellurium(iv) dinitramide compounds R2Te[N(NO2)2] (R = Me, Ph, Mes) and the synthesis of Me3SiN(NO2)2 was achieved. The latter was investigated as potential dinitramide transfer reagent. Furthermore the ionic sulfonium azides [Ph3S]N3 and [Me3S]N3 were prepared and the crystal structure of the triphenylsulfonium salt could be determined. The crystal structure of solvate-free silver dinitramide Ag[N(NO2)2] was elucidated by X-Ray diffraction for the first time. Additionally, in order to achieve a safe handling of the compound, the complete sensitivity data was obtained. The reaction of silver azide with triphenylsulfonium or tetraphenylphosphonium azide results in the formation of the binary silver-nitrogen compound, the novel diazidoargentate(i) anion [Ag(N3)2]– ,initially discovered as a surprising by-product during the preparation of a sulfonium azide. The disproportionation product of the donor-stabilized tellurenyl fluoride 2-Me2NCH2C6H4TeF, the tellurium(iv) trifluoride 2-Me2NCH2C6H4TeF3, could be identified by multinuclear NMR spectroscopy. In addition, the crystal structure of 2-Me2NCH2C6H4TeF3, the second structural characterized tellurium(iv) trifluoride, has been determined. Furthermore the syntheses of the new tellurium(iv) difluoride, (2-Me2NCH2C6H4)2TeF2, and corresponding tellurium(iv) diazide, (2-Me2NCH2C6H4)2Te(N3)2 as well as the tellurium(iv) triazide, 2-Me2NCH2C6H4Te(N3)3, and their characterization by spectroscopic methods were reported. During these investigations rather interesting crystal structures of an organotelluronium salt ([(2-Me2NCH2C6H4)2TeOH]2[SiF6]), a monomeric organotellurium(iv) oxide ((2-Me2NCH2C6H4)2TeO), and an unusual tellurium(vi) species([(2-Me2N(H)CH2C6H4)2TeOF3]2[SiF6]) were elucidated.