Wolfgang Brockner

The Phase Diagram of the System [Ph4P]Br/BiBr3. Synthesis, Crystal Structure, Thermal Behaviour, and Vibrational Spectra of [Ph4P]3[Bi2Br9] · CH3COCH3 and two Modifications of [Ph4P]4[Bi6Br22]

The phase diagram of the system [Ph4P]Br/BiBr3 was investigated with the aid of DSC, TG and temperature dependent X-ray powder diffraction measurements. By varying the reaction conditions, stoichiometry and crystallisation conditions of the reaction between BiBr3 and [Ph4P]Br four polynuclear bromobismuthates are formed. We report here the crystal structure of the solvation product [Ph4P]3[Bi2Br9] · CH3COCH3, which crystallises with monoclinic symmetry in the S. G. P21/nNo. 14, a = 12.341(1), b = 32.005(3), c = 19.929(3) A, β = 99.75(2)°, V = 7758(7) A3, Z = 4 and the crystal structures of two modifications of the compound [Ph4P]4[Bi6Br22]. The α-form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.507(4) A, b = 14.434(4) A, c = 17.709(5) A, α = 81.34(2)°, β = 72.42(2)°, γ = 72.53(2)°, V = 3132.7(1) A3, Z = 2. The high-temperature β-form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.893(4) A, b = 14.267(3) A, c = 16.580(3), α = 100.13(2)°, β = 96.56(2)°, γ = 110.01(2)°, V = 2985.5(1) A3, Z = 2. Lattice parameters of [Ph4P]4[Bi8Br28] are also given. The thermal behaviour of the compounds and in addition the vibrational spectra of [Ph4P]3[Bi2Br9] · CH3COCH3 are presented and discussed. Das Phasendiagram des Systems [Ph4P]Br/BiBr3. Synthese, Kristallstruktur, thermisches Verhalten und Schwingungsspektren von [Ph4P]3[Bi2Br9] · CH3COCH3 und zwei Modifikationen von [Ph4P]4[Bi6Br22] Das Phasendiagram des Systems [Ph4P]Br/BiBr3 wurde mit Hilfe von DSC, TG und temperaturabhangiger Rontgendiffraktometrie untersucht. Durch Variation der Reaktionsbedingungen, der Zusammensetzung und der Kristallisationsbedingungen wurden vier unterschiedliche Bromobismuthate gebildet. Wir berichten uber die Kristallstruktur des Solvatationsproduktes [Ph4P]3[Bi2Br9] · CH3COCH3, das mit monokliner Symmetrie in der Raumgruppe P21/nNo. 14 und den Gitterparametern a = 12.341(1), b = 32.005(3), c = 19.929(3) A, β = 99.75(2)°, V = 7758(7) A3, Z = 4 kristallisiert und die Kristallstrukturen von zwei Modifikationen der Verbindung [Ph4P]4[Bi6Br22]. Die α-Form kristallisiert mit trikliner Symmetrie in der Raumgruppe P1, No. 2, mit den Gitterparametern a = 13.507(4) A, b = 14.434(4) A, c = 17.709(5) A, α = 81.34(2)°, β = 72.42(2)°, γ = 72.53(2)°, V = 3132.7(1) A3, Z = 2. Die Hochtemperaturmodifikation β kristallisiert ebenfalls triklin in der Raumgruppe P1, No. 2 mit den Gitterparametern a = 13.893(4) A, b = 14.267(3) A, c = 16.580(3), α = 100.13(2)°, β = 96.56(2)°, γ = 110.01(2)°, V = 2985.5(1) A3, Z = 2. Die Gitterkonstanten von [Ph4P]4[Bi8Br28] werden ebenfalls angegeben. Das thermische Verhalten der Verbindungen und die Schwingungsspektren von [Ph4P]3[Bi2Br9] · CH3COCH3 werden berichtet.

Scaled quantum mechanical (SQM) calculations and vibrational analyses of the cage-like molecules P4S3, As4Se3, P4Se3, As4S3, and PAs3S3

Abstract Geometry, vibrational frequencies, IR intensities and potential energy distribution are calculated for P4S3 at the SCF/6–31G* level. With one scaling factor all observed frequencies are modelled with an accuracy of ± 1%, and a revised assignment is proposed. Transfer of the P4S3 force field to P4S3, As4Se3, As4S3, and PAs3S3 and rescaling yields a good fit for all these compounds. Where more than one scaling factor is needed, the different scaling factors are explainable. Revised assignments and potential energy distribution data are given for all these compounds. STO-3G* calculations give a poorer fit for P4S3, but with separate scaling of stretching and bending force constants a good fit is obtained.

Crown-ether enclosure generated by ionic liquid components—synthesis, crystal structure and Raman spectra of compounds of imidazolium based salts and 18-crown-6

Bis(1,3-dimethylimidazolium methylsulfate) [18-crown-6] (1), ([DMIm]2[CH3SO4]2[18-crown-6], bis(1-butyl-3-methylimidazolium methylsulfate) [18-crown-6] (2), ([BMIm]2[CH3SO4]2[18-crown-6]), bis(1-ethyl-3-methylimidazolium methanesulfonate) [18-crown-6] (3), ([EMIm]2 [CH3SO3]2[18-crown-6]) and bis(1-ethyl-3-methylimidazolium trifluoromethanesulfonate) [18-crown-6] (4), ([EMIm]2[CF3SO3]2[18-crown-6]) were prepared and characterized by single-crystal X-ray diffraction, NMR and Raman spectroscopy. Coulomb interactions between the ionic (liquid) components as well as hydrogen bonding are important. No significant close contacts are observed between the ionic components and the 18-crown-6 molecules. Crystal structures of all compounds consist of alternated layers of crown-ether molecules and respective ionic units compounds. Within the layers of the ionic components (compounds 1, 3 and 4), two cations are linked to each other by C–H⋯π interactions between one methyl carbon and the imidazolium ring of another cation.

Ramanspektroskopische untersuchungen an antimonpentachlorid. umwandlung momomer-dimer im festen zustand

Zusammenfassung Raman spectra of solid SbCl 5 indicate a structural conversion at −76°C. Above this conversion temperature the spectra are in agreement with the presence of trigonal bipyramidal SbCl 5 -species ( D 3 h ). The Raman spectrum at low temperatures ( 2 Cl 10 -dimers (symmetry D 2 h or C 2 h ).

Ab initio quantum mechanical calculations of energy, geometry, vibrational frequencies and IR intensities of tetraphosphorus tetrasulphide, α-P4S4(D2d), and vibrational analysis of As4S4 and As4Se4

Abstract Geometry, vibrational frequencies and IR intensities are calculated for α-P 4 S 4 by scaled quantum mechanical calculations at the 6-31G*/SCF and STO-3G*/SCF levels. For both basis sets the frequencies are scaled with factors close to or equal to those found for P 4 S 3 , and based on these results a revised assignment is proposed. The α-P 4 S 4 force field is transferred to the isostructural As 4 S 4 and As 4 Se 4 molecules and rescaled, and based on a good fit to experimental frequencies a new assignment is also proposed for these compounds.

Scaled quantum mechanical vibrational analysis of the thiophosphate anions PS3−, PS43−, P2S62− and P2S74−

Based on studies of PS 3 - and PS 4 3- , scaled quantum mechanical vibrational analyses are performed for P 2 S 6 2- (6-31G * level) and P 2 S 7 4- (STO-5G * level). The higher the overall charge density, the higher the required scaling factor, and the larger the inaccuracies of the calculated geometry and vibrational frequencies. Both effects are probably due to neglect of the counterions in the calculations. υ6 in P 2 S 6 2- is conclusively assigned, and its frequency is very sensitive to the basis sets for the d-orbitals and to the counterions

Genetic relationship between intrinsic Raman and infrared fundamental vibrations of the C60 and C70 fullerenes

Abstract High-resolution FT-Raman spectra including solution spectra with polarization measurements, as well as IR spectra of highly purified and analyzed C 60 and C 70 samples were recorded. Semi-empirical Parametric Method 3 (PM3) calculations of all C 60 and C 70 vibrational frequencies were performed. Based on all experimental spectroscopic results, selection rules, PM3 results and computer visualized normal modes of vibration, a correlation, in the sense of a genetic relationship, between C 60 and C 70 vibrations is developed. For the intrinsic C 60 vibrations only one H g mode remains to be assigned tentatively. A complete assignment for all intrinsic C 70 frequencies is proposed. With quite a few exceptions, caused by peculiarities of vibrations of the C 60 and C 70 cluster molecules, observed and calculated vibrational frequencies correlate very well. It is concluded that all cluster vibrations cannot be modeled uniformly.

Scaled quantum mechanical (SQM) vibrational analysis of AlCl3, Al2Cl6 and the free ion AlCl−4

Abstract A series of basis sets are evaluated for AlCl 3 and AlCl − 4 , and a common scaling factor derived for these compounds was transferred to Al 2 Cl 6 . 6-31G* calculations, scaled with a common factor of 0.92, give a good fit to all vibrational frequencies for AlCl 3 , AlCl − 4 and Al 2 Cl 6 , and there is also a qualitative fit between calculated and observed IR intensities. Extending the basis set does not lead to significant improvements, either for the geometry or for the vibrational frequencies. The calculations verify earlier assignments based on general valence force fields and predict frequencies for some unobserved bands. The SQM force fields for aluminium chlorides show large similarities with the isoelectronic thiophosphates; the main deviations can be attributed to more ionic bonds in the aluminium chlorides. A significant influence on the out-of-plane vibration in AlCl 3 by the basis set on the d -orbitals may indicate that π dp bonding plays a role. A remarkable and unexpected basis set sensitivity is found for the ν 6 ( B 1 g ) ring vibration in Al 2 Cl 6 .

Kristallstruktur und Schwingungsspektren des Thalliumhexathiometadiphosphates Tl2P2S6 / Crystal Structure and Vibrational Spectra of Tl2P2S6

Tl2P2S6 crystallizes in the orthorhombic system, space group Immm, Z = 2 with the lattice constants a = 793.2(4) pm, b = 689.2(4) pm, c = 901.9(5) pm. In the structure there are discrete P2S62- -anions. The P2S62- -ion was found to be a hexa-thiometadiphosphate group where the two P atoms are linked by two S bridges. Far infrared, infrared and Raman spectra of this compound have been recorded. The observed frequencies are assigned on the basis of P2S62- units with D2h symmetry in analogy to the isoelectronic Al2Cl6

Structural and spectroscopic elucidation of imidazolium and pyridinium based hexachloridophosphates and niobates

1-Ethyl-3-methylimidazolium hexachloridophosphate, [EMIm][PCl6] (1), 1-ethyl-3-methylimidazolium hexachloridoniobate, [EMIm][NbCl6] (2), 1-butyl-4-methylpyridinium hexachloridophosphate, [1,4-BMPy][PCl6] (3), 1-butyl-4-methylpyridinium hexachloridoniobate, [1,4-BMPy][NbCl6] (4), and 1-butyl-3-methylpyridinium hexachloridoniobate, [1,3-BMPy] [NbCl6] (5) have been synthesized and characterized by single-crystal X-ray diffraction and Raman spectroscopy. All the saltlike compounds crystallize in the monoclinic space group: [EMIm][PCl6] (1): P21/c (no. 14), a = 7.698(1), b = 12.266(2), c = 15.019(2) A, β = 101.45(1)°, V = 1389.9(3) A3 and Z = 4; [EMIm][NbCl6] (2): P21/n (no. 14), a = 20.186(1), b = 7.084(1), c = 20.549(1) A, β = 98.46(1)°, V = 2906.6(4) A3 and Z = 8; [1,4-BMPy][PCl6] (3): P21/c (no. 14), a = 14.681(2), b = 7.242(1), c = 16.157(2) A, β = 101.55(1)°, V = 1683.0(3) A3 and Z = 4; [1,4-BMPy][NbCl6] (4): P21/c (no. 14), a = 15.163(2), b = 7.323(1), c = 16.205(2) A, β = 101.92(1)°, V = 1760.5(4) A3 and Z = 4; [1,3-BMPy][NbCl6] (5): P21/c (no. 14), a = 10.396(1), b = 23.050(2), c = 14.974(2) A, β = 102.28(1)°, V = 3505.9(6) A3 and Z = 8. Title compounds are built up by the mentioned bulky organic cations and octahedral [PCl6]−respective [NbCl6]− anions. No significant hydrogen bonding is observed between the organic cations and respective inorganic anions. FT-Raman spectra of the title compounds have been recorded and interpreted, especially with respect to the inorganic parts [PCl6]− and [NbCl6]−. NMR spectra and the melting temperatures of 1–5 are given.