An organometallic chimie douce approach to new Re(x)W(1-x)O3 phases

Re(x)W(1-x)O3.H2O and Re(x)W(1-x)O3 phases are prepared by a new organometallic chimie douce concept employing the organometallic precursor methyltrioxorhenium.Comment: 3 pages, 6 figures, submitted to Chem. Com

Two Ti-doped distrontium ruthenium tetraoxides: Sr2Ru0.93Ti0.07O4 and Sr2Ru0.81Ti0.19O4

Two Ti-doped distrontium ruthenium tetraoxides: Sr2Ru0.93Ti0.07O4 and Sr2Ru0.81Ti0.19O4 / J. Hanss ... - In: Acta crystallographica. C. 59. 2003. S. i35-i3

The energy of interaction between water and surfaces of biological reference materials

The energy of interaction between water and surfaces of biological reference materials / J. Hanss ... - In: Food chemistry. 82. 2003. S. 51-5

Synthesis of Mesoporous Metal Oxides by Structure Replication: Thermal Analysis of Metal Nitrates in Porous Carbon Matrices

A variety of metal nitrates were filled into the pores of an ordered mesoporous CMK-3 carbon matrix by solution-based impregnation. Thermal conversion of the metal nitrates into the respective metal oxides, and subsequent removal of the carbon matrix by thermal combustion, provides a versatile means to prepare mesoporous metal oxides (so-called nanocasting). This study aims to monitor the thermally induced processes by thermogravimetric analysis (TGA), coupled with mass ion detection (MS). The highly dispersed metal nitrates in the pores of the carbon matrix tend to react to the respective metal oxides at lower temperature than reported in the literature for pure, i.e., carbon-free, metal nitrates. The subsequent thermal combustion of the CMK-3 carbon matrix also occurs at lower temperature, which is explained by a catalytic effect of the metal oxides present in the pores. This catalytic effect is particularly strong for oxides of redox active metals, such as transition group VII and VIII metals (Mn, Fe, Co, Ni), Cu, and Ce

Elucidating gating effects for hydrogen sorption in MFU-4-type triazolate-based metal-organic frameworks featuring different pore sizes

10sinoneA highly porous member of isoreticular MFU-4-type frameworks, [Zn 5Cl4(BTDD)3] (MFU-4l(arge)) (H 2-BTDD=bis(1H-1,2,3-triazolo[4,5-b],[4′,5′-i])dibenzo[1, 4]dioxin), has been synthesized using ZnCl2 and H2-BTDD in N,N-dimethylformamide as a solvent. MFU-4l represents the first example of MFU-4-type frameworks featuring large pore apertures of 9.1a Å Here, MFU-4l serves as a reference compound to evaluate the origin of unique and specific gas-sorption properties of MFU-4, reported previously. The latter framework features narrow-sized pores of 2.5a Å that allow passage of sufficiently small molecules only (such as hydrogen or water), whereas molecules with larger kinetic diameters (e.g., argon or nitrogen) are excluded from uptake. The crystal structure of MFU-4l has been solved ab initio by direct methods from 3D electron-diffraction data acquired from a single nanosized crystal through automated electron diffraction tomography (ADT) in combination with electron-beam precession. Independently, it has been solved using powder X-ray diffraction. Thermogravimetric analysis (TGA) and variable-temperature X-ray powder diffraction (XRPD) experiments carried out on MFU-4l indicate that it is stable up to 500°C (N2 atmosphere) and up to 350°C in air. The framework adsorbs 4a wt% hydrogen at 20a bar and 77a K, which is twice the amount compared to MFU-4. The isosteric heat of adsorption starts for low surface coverage at 5a kJmol-1 and decreases to 3.5a kJmol -1 at higher H2 uptake. In contrast, MFU-4 possesses a nearly constant isosteric heat of adsorption of ca. 7a kJmol-1 over a wide range of surface coverage. Moreover, MFU-4 exhibits a H2 desorption maximum at 71a K, which is the highest temperature ever measured for hydrogen physisorbed on metal-organic frameworks (MOFs). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.noneDenysenko, D.;Grzywa, M.;Tonigold, M.;Streppel, B.;Krkljus, I.;Hirscher, M.;MUGNAIOLI, E.;Kolb, U.;Hanss, J.;Volkmer, D.Denysenko, D.; Grzywa, M.; Tonigold, M.; Streppel, B.; Krkljus, I.; Hirscher, M.; Mugnaioli, E.; Kolb, U.; Hanss, J.; Volkmer, D

Water and bromide in the active center of vanadate-dependent haloperoxidases

Water and bromide in the active center of vanadate-dependent haloperoxidases / J. Hanss ... - In: Journal of inorganic biochemistry. 80. 2000. S. 115-12