Jussi Valkonen

Crystal and molecular structure of anhydrous betaine, (CH3)3NCH2CO2

Abstract 1–Carboxy–N,N,N–trimethylmethanamanium inner salt or anhydrous betaine, (CH3)3NCH2CO2, FW=117.15 gmol −1 , crystallizes in the orthorhombic space group Pnma with a=14.544(2) A , b=6.859(3) A , c=6.131(1) A , V=611.7(3) A 3 , Z=4, D x =1.27 Mgm −3 , λ (MoK α )=0.71073 A , μ =0.091 mm −1 . The structure was resolved by direct methods and refined by least-square calculations to R=0.038 for 531 reflections. Observed changes in bond angles imply that there is a repulsion between nitrogen and oxygen. The melting point (measured at onset) is 570xa0K. FTIR spectra of anhydrous betaine and monohydrate were recorded. Clear differences were found between the two compounds based on infrared (i.r.) absorption bands sensitive to water.

Mononuclear cis-dioxovanadium(V) anionic complexes [VO2L]–{H2L =[1 + 1] Schiff base derived from salicylaldehyde (or substituted derivatives) and 2-amino-2-methylpropan-l-ol}: synthesis, structure, spectroscopy, electrochemistry and reactivity studies

The compounds [H3NCMe2CH2OH][VO2L]{H2L =[1 + 1] Schiff base derived from salicyladehyde (or substituted derivatives) and 2-amino-2-methylpropan-l-ol} have been synthesized in good yields by reaction of the Schiff base (formed in situ) and a further equivalent of the amino alcohol with [VO(acac)2](Hacac = acetylacetone). The structures of three of the complexes have been solved by single-crystal X-ray studies. All the compounds were also characterized by UV/VIS, FTIR and NMR spectroscopy and by cyclic voltammetry. The three structurally characterized mononuclear complexes contain the cis-dioxovanadium(V) moiety and exhibit distorted square-pyramidal geometry at vanadium which is displaced from the equatorial plane by ≈ 0.5 A. The crystal and molecular structures of these compounds showed extensive hydrogen bonding between the anionic portion of the complexes and the counter-cations of the amino alcohol which resulted in some unusual metric features of interest to the binding of vanadium in biological systems. Two of the compounds showed the longest VO distances reported so far for mononuclear cis-dioxovanadium(V) complexes. Three of the complexes undergo photoreduction in the solid state which is attributed to their intermolecular interactions in the crystal.

Crystal structures, infrared-spectra, and thermal behavior of calcium hydrogenselenite monohydrate, Ca(HSeO3)2•H2O, and dicalcium diselenite bis (hydrogenselenite), Ca2(HSeO3)2(Se2O5)

Abstract Calcium hydrogenselenite monohydrate and dicalcium diselenite bis(hydrogenselenite) were synthesized and their crystal structures determined. Crystal data for Ca(HSeO3)2 · H2O: a = 6.911(2), b = 7.369(2), c = 6.739(2) A, α = 90.51(3)°, β = 90.93(3)°, γ = 107.46(2)°, V = 327.3(2) A3, space group P 1 (No. 2), dcalcd = 3.19 M gm−3, Z = 2, and R = 0.036 for 1503 reflections. Data for Ca2(HSeO3)2(Se2O5): a = 14.719(4), b = 7.059(2), c = 11.793(2) A, β = 117.96(2)°, V = 1082.3(4) A3, space group C2 c (No. 15), dcalcd = 3.52 Mg m−3, Z = 4, and R = 0.047 for 1251 reflections. Both structures form a three-dimensional network. The coordination polyhedron around calcium is a monocapped trigonal prism in dicalcium diselenite bis(hydrogenselenite) and a bicapped trigonal prism in calcium hydrogenselenite monohydrate. The Caue5f8O distance varies from 2.368 to 2.615 A. Thermal behavior was investigated and the infrared spectrum assigned for dicalcium diselenite bis(Hydrogenselenite).

Characterization of the non-stoichiometry in lanthanum oxyfluoride by FT-IR absorption, Raman scattering, X-ray powder diffraction and thermal analysis

Abstract The FT-IR absorption, FT-Raman scattering, X-ray powder diffraction (XPD), and thermogravimetry were used to explore the non-stoichiometry in LaOF. The TGA-DTA analyses between 30 and 1500°C showed that the LaO1 − xF1 + 2x phases yielded the stoichiometric LaOF as an intermediate product. The temperature of formation of the LaOF and La2O3 increased with increasing excess of fluoride. The room temperature XPD data in 6.5 ⩽ 2θ ⩽ 121° range were analyzed by the Rietveld profile refinement method and subsequently by the bond valence calculations. All LaO1 − xF1 + 2x phases possess the tetragonal PbFCl-type structure (space group: P4/nmm; Z = 2) while the stoichiometric LaOF has the hexagonal SmSI-type structure (space group: R 3 m; Z = 6 ). The unit cell parameters a and c as well as the global instability index (GII) values increased with increasing excess fluoride. The GII value for each LaO1 − xF1 + 2x exceeded the limit (ca 0.2) for a possible breakdown of the tetragonal structure indicating the inherent instability of these phases. The room temperature FTIR and FT-Raman spectra between 100 and 500 cm−1 and 50 and 1000 cm−1, respectively, were investigated using the factor group analysis to get more information of the local structure in LaOF. All four IR modes (2A2u + 2Eu) the for both forms and five of the six Raman modes (3A1g + 3Eg and A1g + 2B1g + 3Eg) for the hexagonal and the tetragonal form, respectively, were observed. The Raman spectra of the tetragonal LaOCl and all LaO1 − xF1 + 2x were found remarkably similar.

Halogenation of tellurium by SO2Cl2. Formation and crystal structures of (H3O)[Te3Cl13]·1/2SO2, [(C4H8O)2H][TeCl5]·(C4H8O), [(Me2SO)2H]2[TeCl6], and [Ni(NCCH3)6][Te2Cl10]

Abstract The halogenation of elemental tellurium with SO2Cl2 in various solvents has been investigated. (H3O)[Te3Cl13]·1/2SO2 (1) and [(C4H8O)2H][TeCl5]·(C4H8O) (2) were obtained in CS2 and THF, respectively. When DMSO is added into the THF solution of tellurium and SO2Cl2, [(Me2SO)2H]2[TeCl6] (3) is formed. In the acetonitrile solution tellurium and SO2Cl2 form [Ni(NCCH3)6][Te2Cl10] (4) in the presence of metallic nickel. All compounds 1–4 were characterized by 125Te NMR and by X-ray crystallography. The formation of the anions has been discussed.

Simultaneous application of Fourier transform Raman spectroscopy and differential scanning colorimetry for the in situ investigation of phase transitions in condensed matter

Abstract The combination of Fourier transform Raman spectroscopy with differential scanning colorimetry for the in situ investigation of phase transitions is illustrated using ammonium nitrate as an example. This method helps unambiguous characterisation of different phases by providing a simultaneous probe of thermodynamic and vibrational data.

Physicochemical Properties of New Dicationic Ether-Functionalized Low Melting Point Ammonium Salts

Eleven new and one previously known but insufficiently characterized dicationic quaternary ammonium (QA) salts were synthesized and characterized. They contain an ethoxy ethyl group either in a side chain and/or as spacer of the diammonium cation and have bromide, hexafluorophosphate (PF6–), bis(trifluoromethanesulfonyl)imide (TFSI), or trifluoromethanesulfonate (TFMS) as an anion. 1H and 13C techniques, mass spectrometry, and elemental analysis together with X-ray diffraction and thermoanalytical methods were used for their characterization both in the liquid and solid state. In addition, residual water content and viscosity measurements were made for the two room temperature ionic liquids (RTILs). Capillary electrophoresis was used to measure the conductivity of the RTILs. Crystal structures of four compounds were determined by X-ray single crystal diffraction, and powder diffraction was used to study the crystallinity of the solid salts and to compare the structural similarities between the single crystals and the microcrystalline bulk form. Two of the TFSI salts were liquids below room temperature, having liquid ranges of ~380 and 350°C, respectively, and seven out of 12 salts melted below 100°C. In addition, both the TFSI and PF6 salts exhibited high thermal stabilities decomposing at about, or above 300°C. Both RTILs presented moderate viscosities at elevated temperatures. The determined physicochemical properties of the reported ILs suggest their applicability for various applications such as heat transfer fluids, high temperature synthesis, and lubricants.

Spectroscopic and Structural Properties of Ca1-xSrxAl2O4:Eu2☎, RE3☎ Persistent Luminescence Materials

The preparation, structure and luminescence of the Ca1-xSrxAl2O4:Eu2☎, RE3☎ system were studied. Monoclinic CaAl2O4 was the major phase when the strontium content x was from 0 to 0.6, but hexagonal SrAl2O4 was obtained when x was 0.8 and monoclinic SrAl2O4 when x was 1. Only slight Ca/Sr cation solid solubility was observed. The strontium ions dissolved better into the CaAl2O4 phase than vice versa. Two luminescence bands were observed for mixed compositions, peaking at 440 and 530 nm, corresponding to those of the monoclinic CaAl2O4:Eu2☎ and hexagonal SrAl2O4:Eu2☎ ones. The persistent luminescence was enhanced by the Ca/Sr replacement. This observation supports the mechanisms where the lattice defects act as traps.

Crystal structure of lactitol (4-O-β-d-galactopyranosyl-d-glucitol)

Abstract Lacitol, C 12 H 24 O 11 , is monoclinic, space group P 2 1 with cell dimensions a = 7.614(1), b = 10.757(1), c = 9.370(1) A, β = 108.19(1)°, and V = 729.0(1) A 3 ; Z = 2, D x = 1.57 Mg.m −3 , λ(Cu- K α ) = 1.5406 A, μ = 1.166 mm −1 , F (000) = 368, and T = 23°. The structure was solved by direct methods and refined by least-squares calculations to R = 0.048 for 1510 unique observed reflections. There are one intra- and eight inter-molecular hydrogen bonds in the structure. Bond lengths and angles accord well with the mean values of related structures. The galactopyranosyl ring has a chair conformation.

The crystal structure of neodymium and europium chromate heptahydrate: Synthesis, infrared spectra, and thermal behavior of lanthanoid chromate heptahydrates, [Ln2(CrO4)3(H2O)5] · 2H2O (Ln = La, Pr, Nd, Sm, Eu, Gd)

Abstract The crystal structures of Nd2(CrO4)3 · 7H2O and Eu2(CrO4)3 · 7H2O were determined by the conventional single-crystal X-ray diffraction technique. In addition, unit cell dimensions were measured for La2 (CrO4)3 · 7H2O and Sm2(CrO4)3 · 7H2O. All these compounds are isostructural. Crystals are monoclinic, space group P2 1 c . For Nd2(CrO4)3 · 7H2O, a = 8.052(4) A, b = 19.143(4) A, c = 13.326(6) A, β = 128.15(4)°, Z = 4, Dx = 3.14 Mg · m−3, T = 296(1); and for Eu2(CrO4)3 · 7H2O, a = 7.965(3) A, b = 18.985(4) A, c = 13.185(4) A, β = 128.00(2)°, Z = 4, Dx = 3.29 Mg · m−3, T = 296(1). Ln atoms are nine-coordinated so that the coordination polyhedron is a tricapped trigonal prism for Ln1 and a monocapped square antiprism for Ln2. Structures form a three-dimensional network. Unit cell dimensions for La2(CrO4)3 · 7H2O are a = 8.181(6) A, b = 19.294(6) A, c = 13.436(8) A, β = 128.09(6)° and those for Sm2(CrO4)3 · 7H2O are a = 7.975(9) A, b = 19.00(1) A, c = 13.18(3) A and β = 127.5(2)°. Thermal behavior was investigated and IR spectra were recorded for Ln2(CrO4)3 · 7H2O (Ln = La, Pr, Nd, Sm, Eu, Gd).