Wolfgang Sundermeyer

The GeSi bond in silylgermane. Discrepancy between experiment and theory

Abstract The gas-phase structure of H 3 GeSiH 3 was determined by joint analysis of electron diffraction intensities and the rotational constant. The following geometric parameters ( r a distances and ∠ α angles with 2σ uncertainties) were obtained: GeSi = 2.364(1), GeH = 1.538(3), SiH = 1.494(6) A, HGeH = HSiH = 108.8(3)°. The experimental GeSi bond length is 0.04–0.07 A shorter than various ab initio results reported in the literature.

Beiträge zur Chemie der Kohlensäurederivate, 3. Mitt.: Neue Synthesen von Tris(trimethylsilyl) cyanurat,N-Chlorsulfinylimid und Chlorcyan

Tris(trimethylsilyl)cyanurate (I) has been prepared in high yields by silylation of cyanuric acid with trimethylsilyl cyanide, as well as by the reaction of trichloroisocyanuric acid with trimethylsilyl cyanide or trimethylsilylsulfinylimide. The latter reactions, yielding Cl−CN and Cl−NSO resp. as the only by-products, are convenient methods for synthesizing these pseudohalogen-chloride compounds in a very pure state. Starting fromN-chlorocarbonyl isocyanateI is formed in high yields by a complex reaction with trimethylsilylsulfinylimide too. Based on IR, Raman and1H-NMR data the O-silyl structure ofI was confirmed. The formation of products with N-silyl or N,O-silyl structure was never observed.

Reaktionen des fluorcyans, FCN

Abstract By reaction of cyanogen fluoride with fluorine compounds like COF 2 , SF 4 , SOF 4 and HF in the presence of nucleophilic catalysts the addition products CF 3 NCO, CF 3 NSF 2 , CF 3 NSOF 2 and CF 3 NH 2 could be obtained together with polymer and copolymer products of FCN. By rearrangement and further reaction of intermediates also CF 3 OCOF, (CF 3 ) 2 NCOF and the hitherto unknown compounds CF 3 N(CN) 2 and F 2 CNCF 2 NSOF 2 are formed.

Charakterisierung und photochemie von (dihalogenmethylen)sulfoxiden, XYCSO

Abstract Dihalogenomethylene sulfoxides (dihalogenosulfines) 2a – c were generated by flash vacuum pyrolysis of 2,2,4,4-tetrahalogeno-1,3-dithietane 1,3-dioxides 1a – c and trapping the pyrolysis products in argon at 10 K. At room temperature unstable difluorosulfine ( 2a ) and chlorofluorosulfine ( 2b ) were identified by i.r. spectroscopy, and the photochemistry of the sulfines was investigated. Chlorofluorosulfine ( 2b ) exists in two geometrical isomers. Photolysis of 2a leads to fragmentation to give CF 2 and SO, photolysis of the chlorine containing sulfines 2b and 2c to rearrangement to give the sulfenyl chlorides 6 and 8 . This is explained by different migratory tendencies of fluorine and chlorine and the stability of the CF bond.

Oxidative direktfluorierung perhalogenierter 1,3-dithietane

Abstract S-fluorinated perhalo-1,3-dithietanes: 1,1,2,2,4,4-hexafluoro-l,3-dithietane (2), 1,1,2,2,3,3,4,4-octafluoro-l,3-dithietane (3), 1,1-dioxo-2,2,3,3,4,4-hexafluoro-1,3-dithietane (5), 1,1-difluoro-3,3-dioxo-2,2,4,4-tetrachloro-l,3-dithietane (7). could be obtained by application of the fluid-phase low temperature fluorination. MS-, NMR-, IR-spectra and elementary analyses are reported.

Oxidative fluorierung perhalogenierter 1,3-dithietane

Abstract 2-Chloro-1,1,2,3,3,4,4,-heptafluoro-1,3-dithietane (7b), 2,4-dichloro-1,1,2,3,3,4-hexafluoro-1,3-dithietane (7c), 2-chloro-1,1,2,4,4-pentafluoro-3,3-dioxo-1,3-dithietane (9b), 2,4-dichloro-1,1,2,4-tetrafluoro-3,3-dioxo-1,3-dithietane (9c), and 1,1,2,2,4,4-hexafluoro-3-oxo-1,3-dithietane (14) were synthesized by liquid-phase/low-temperature fluorination or with xenon difluoride. They were characterized by elemental analysis, MS-, NMR- and IR-spectroscopy. New syntheses of 2,2,4,4-tetrafluoro-1,3-dioxo-1,3-dithietane (12) and 1,1,2,2,4,4-hexafluoro-3,3-dioxo-1,3-dithietane (3) are reported.

Perfluoralkyl ― und Fluorcarbonyl-Hydrazine

Abstract A versatile method for the synthesis of fluorocarbonyl hydrazines by reaction of xenon difluoride and isocyanates is described together with the preparation of tetrakis(trifluoromethyl) hydrazine from perfluoroazapropene. Methoxycarbonyl substituted hydrazines could be obtained by reaction of fluorocarbonyl hydrazines and methanol.

Chlor-trifluormethyl-sulfin, CF3CL=SO

Abstract Chloro-trifluoromethylsulfine (6) could be synthesized by two independent methods. The two isomers observed are of unexpected different stability at room temperature.

Zur synthese perhalogenierter 1,3-dithietan-s-oxide und thiirane

Abstract 2,2-Dichloro-3,3-bis(trifluoromethyl) thiirane 4 and 2- chloro-2-fluoro-3,3-bis(trifluoromethyl) thiirane 5 were synthesized by the reaction of bis(trifluoromethyl)diazomethane 1 with thiophosgene 2 or chlorofluorothiocarbonyl 3 . Starting from the 1,3-dithietanes 6 and 10 the 1,3-dithietane-S-oxides 7, 8, 11 and 13 could be obtained by use of various oxidation agents. 2,3-Dichloro-2,3-bis(trifluoromethyl) thiirane 9 and 2,2,3-trichloro-3-fluoro thiirane 12 were isolated by thermolysis (FVP) of the two 1,3-dithietane-1,1-dioxides 7 and 11 under SO 2 extrusion.

Zur Synthese des 2-Chlor-2,4,4-Trifluor-1,3-Dithietans und seiner S-Oxide

Abstract The series of 2-chloro-2,4,4,-trifluoro-1,3-dithietane-S-oxides could be synthesized, e.g. the 1-oxide 3, 1,1,-dioxide 4, 1,3-dioxide 6, 1,1,3-trioxide 7 and 1,1,3,3,-tetroxide 5. From 7 the sulfone HF 2 C-SO 2 -CClFH (8) could be obtained by hydrolysis in methanol. All compounds were identified by MS-, NMR-, IR-spectra and elementary analyses. The sulfines F 2 C=SO and ClFC=SO were detected in an argon matrix after vacuum pyrolysis of 6.