Rolf Minkwitz

Dimethyl germylene insertion into a strained C-Ge bond and matrix isolation of tetramethyl digermene Me2Ge=GeMe2

Abstract Free tetramethyl digermene Me 2 Ge=GeMe 2 is generated thermally from molten 7,8-digerma bicyclooctadienes[2.2.2] which are obtained by germylene (Me 2 Ge) insertion into the C-Ge bond of corresponding 7-germa norbornadienes. The structure of the digermene follows from MS, matrix IR and Raman spectroscopy.

Trihydroxycarbenium Hexafluorometalates: Salts of Protonated Carbonic Acid

Stabilization by salt formation: carbonic acid, which is not available as a pure substance, was isolated in the form of its trihydroxycarbenium salts, C(OH)3+  MF6- (M=As, Sb), from the reaction of carbonic acid bis(trimethylsilyl) ester in the superacids HF/MF5 . The structure of the cation is shown in the picture. The ion was also characterized by vibrational spectroscopic studies.

The anomeric effect in trifluoromethoxy methane, CF3OCH3

Abstract The molecular structure of trifluoromethoxy methane was determined by a joint analysis of gas diffraction intensities and rotational constants, incorporating a normal coordinate analysis, in order to test the predictions of the stereoelectronic effects model, the generalized anomeric effect. Due to the internal rotation of the methyl group, some lines were split and the torsional barrier, V 3 (CH 3 ) = 382 (10) cm −1 , could be determined. The rotational constants are: B 0 = 3069.253 (48) and C 0 = 3045.581 (48) MHz. Ab initio calculations at different levels of theory helped to interpret the data. The following structural parameters were derived ( r z parameters in A and bond angles in degrees): OC H : 1.426 (9); OC F : 1.347 (9); CF t : 1.318 (7); CF g : 1.336 (5); (CH) mean : 1.095 (24); COC: 115.5 (4); (FCF) mean : 107.7 (4); (HCH) mean : 111.1 (19); OCF t : 109.0 (8); OCF g : 112.3 (7). The structure fully confirms the predictions of the anomeric effect model.

Neuartige elementorganische Sauerstoffsäuren des Phosphors und Schwefels [1]†

Die neuartige Imidazoliophosphonsaure Im—PO3H (7, Im = 2-{1, 3-diisopropyl-4, 5-dimethylimidazolio}) wird durch Hydrolyse des Phosphonylchlorids [Im-P(O)Cl2]Cl (6), das durch direkte Umsetzung des stabilen 2, 3-dihydro-1, 3-diisopropyl-4, 5-dimethylimidazol-2-ylidens (5) mit P(O)Cl3 zuganglich ist, erhalten. Die neuartige kationische Sulfonsaure [Im—SO3H]X ist als BF4- bzw. SbF6-Salz (11a, b) durch Umsetzung des Betains Im—SO3 (10) mit HBF4· Et2O bzw. HF/SbF5 zuganglich. Die Kristallstrukturen von 7 und 11b werden ermittelt und diskutiert. Novel Elementorganic Oxo-Acids of Phosphorus and Sulfur [1] The novel imidazoliophosphonate acid Im—PO3H (7, Im = 2-{1, 3-diisopropyl-4, 5-dimethylimidazolio}) is prepared through hydrolysis of the phosphonyl chloride [Im—P(O)Cl2]Cl (6) formed by the direct reaction of the stable 2, 3-dihydro-1, 3-diisopropyl-4, 5-dimethylimidazol-2-ylidene (5) with P(O)Cl3. The novel cat ionic sulfonic acid [Im—SO3H]X (11) is formed as its BF4 (11a) and SbF6 (11b) salt on treatment of the betaine Im—SO3 (10) with HBF4· Et2O or HF/SbF5. The crystal structures of 7 and 11b are reported and discussed.

Bis(trifluoromethyl)fluorsulfonium(IV)-metallate(V) [1] (CF3)2SF+MF6- (M = As, Sb)

Abstract The preparation of (CF 3 ) 2 SF + MF 6 - (M = As, Sb) is reported. New salts have been synthesized from the reaction of (CF 3 ) 2 SF 2 with strong Lewis acids and CF 3 SCF 3 with XeF + MF 6 - (M = As, Sb). They are characterised by Raman- and NMR - spectroscopy.

Conformations and structures of thiophosphanes containing one, two and three PS bonds. A gas electron diffraction and ab initio study

Abstract The conformations and geometric structures of thiophosphanes which contain one PS bond, X 2 PSY, two PS bonds, XP(SY) 2 and three PS bonds, P(SY) 3 are studied by ab initio calculations and gas electron diffraction (GED). For compounds of the type X 2 PSY (X  H or F and YH, CH 3 or F) the calculations predict two possible conformations with the SY bond either synperiplanar to the phosphorus lone pair (Θ (1pPSY)  0°) or antiperiplanar (Θ = 180°). The synperiplanar structure is preferred in compounds with equivalent substituents (H 2 PSH and F 2 PSF), whereas the antiperiplanar form is preferred for mixed substituents (F 2 PSH, F 2 PSCH 3 and H 2 PSF). A GED study of (CF 3 ) 2 PSCF 3 results in a synperiplanar structure (Θ = 0°), confirming this observation. Calculations for HP(SH) 2 result in three stable structures, syn—syn ( C s symmetry), syn—anti ( C 1 symmetry) and anti—anti ( C s symmetry). The relative energies are predicted to be 0, 0.46 and 1.26 kcal mol −1 (HF/3-21G*). In the case of HP(SCF 3 ) 2 the calculated energy of the syn—anti form relative to the syn—syn form depends on the basis set; −1.32 kcal mol −1 for HF/3-21G* and 0.23 kcal mol −1 for HF/6-31G**. According to the GED analysis, the prevailing conformer of this thiophosphane is syn—syn with a possible small contribution of the syn—anti form. The parent thiophosphane with three PS bonds, P(SH) 3 , posseses five possible conformations, two of which have C 3 symmetry, two C s symmetry and one C 1 symmetry. For P(SCF 3 ) 3 two of these five forms possess unreasonably short F⋰F contacts between neighboring CF 3 groups and do not form stable structures. According to the GED analysis the main conformer of P(SCF) 3 ) 3 possesses C 3 symmetry with all CF 3 groups syn to the phosphorus lone pair (Θ 1 = Θ 2 = Θ 3 = 29(4)°). Small contributions ( C s and/or C 1 structures cannot be excluded.

Synthesis and Characterization of the Tetrahydroxyphosphonium Hexafluorometalates P(OH)4+MF6− (M=As, Sb)

At last, structural characterization of the P(OH)4+ ion (1; see picture) has been achieved through the transformation of H3PO4 with HF/MF5 (M=As, Sb). The phosphorus acids H3POn (n=2–4) react differently in the superacidic systems HF/MF5 (M=As, Sb): H3PO2 and H3PO3F form fluorophosphanes and hydronium salts, while H3PO4 gives thermolabile salts. The antimony compound P(OH)4+SbF6− has been crystallized and its crystal structure determined.

Synthese der monofluorammoniumsalze NH3F+HF2-·nHF, -SbF6-, -AsF6-, -BF4-

Abstract The reaction of N-fluoroisopropylcarbamate in anhydrous HF yields the new monofluoroammonium salt NH3F+HF2-·nHF. This compound may be used for the synthesis of further monofluoroammonium salts with complex fluoroanions. Mass spectroscopic investigations of volatile monofluoroammonium salts give evidence for the presence of the yet unknown monofluoramine in the gaseous phase.

Caesium-tetrafluor(trifluormethyl)sulfat(IV) [1]

Abstract The preparation of Cs + CF 3 SF 4 − is reported. The new salt is characterized by vibrational (IR, RA) and nuclear magnetic resonance ( 19 F, 13 C) spectra.

Beiträge zur chemie der schwefelhalogenide. 10. [1] Matrixisolation von SCl3F, SCl2F2 und SClF3

Abstract We report the matrix isolation of the sulfuranes SCl3F, SCl2F2, SClF3. They are formed in the gas phase during the cocondensation of SCl2 with ClF and F2, respectively. We measured the complete vibrational spectrum of SCl2F2, the most stable species in this series. The assignment is based on a C2v model and is supported by a normal coordinate analysis. For SCl3F and SClF3 the stretching modes are given.