Search results for "Tellurium"

Ruthenium‐assisted tellurium abstraction in bis(thiophen‐2‐yl) ditelluride

2023

The reaction of [RuCl2(CO)3]2 and Te2Tpn2 (Tpn = thiophen-2-yl, C4H3S) in the absence of light resulted in the formation of cct-[RuCl2(CO)2(TeTpn2)2] (1) [cis(Cl)-cis(CO)-trans(TeTpn2)] and TeTpn2 (2) together with the precipitation of tellurium. The complex 1 and the monotelluride 2 were characterized by NMR spectroscopy and single-crystal X-ray diffraction. The decomposition of Te2Tpn2 to TeTpn2 has been monitored by 125Te NMR spectroscopy and seemed to be faster than the ligand substitution in [RuCl2(CO)3]2 by TeTpn2. A catalytic cycle is proposed for the decomposition of Te2Tpn2 to TeTpn2 based on the PBE0-D3/def2-TZVP calculations. peerReviewed

Mo-containing tetragonal tungsten bronzes. The influence of tellurium on catalytic behaviour in selective oxidation of propene

2009

Abstract Te-free and Te-containing multicomponent Mo-based catalysts presenting tetragonal tungsten bronze (TTB) structure have been prepared, characterized and tested for the selective oxidation of propene. The catalysts were prepared hydrothermally and heat treated at 700 °C. The structural characterization performed by means of XRD, FTIR, SAED and HRTEM confirms the incorporation of tellurium to the TTB structural framework and shows that its presence does not modify in essence the crystalline structure. However, the incorporation of Te strongly modifies the catalytic performance, and the highest yield to acrolein has been achieved on catalysts with Te/Mo atomic ratios in bulk of 0.03. T…

Chemical reactions in a gas-jet recoil-transport system: Continuous separation procedure for selenium and tellurium from fission products

1978

Abstract Chemical selectivity in a gas-jet recoil-transport system can be achieved by chemical reactions with the carrier gas. This is demonstrated for an ethylene-nitrogen jet in which volatile species of selenium and tellurium are formed by passing the gas through a reaction zone heated to 860°C. Rapid continuous separation procedures for selenium and tellurium from fission products based on this effect are described and some decay data of the neutron-rich nuclides 85–88Se and 135–137Te obtained with these methods are given.

Bio serves nano: biological light-harvesting complex as energy donor for semiconductor quantum dots.

2012

Light-harvesting complex (LHCII) of the photosynthetic apparatus in plants is attached to type-II core-shell CdTe/CdSe/ZnS nanocrystals (quantum dots, QD) exhibiting an absorption band at 710 nm and carrying a dihydrolipoic acid coating for water solubility. LHCII stays functional upon binding to the QD surface and enhances the light utilization of the QDs significantly, similar to its light-harvesting function in photosynthesis. Electronic excitation energy transfer of about 50% efficiency is shown by donor (LHCII) fluorescence quenching as well as sensitized acceptor (QD) emission and corroborated by time-resolved fluorescence measurements. The energy transfer efficiency is commensurable …

Molecular structures of Se(SCH3)2 and Te(SCH3)2 using gas-phase electron diffraction and ab initio and DFT geometry optimisations

2005

The molecular structures of Se(SCH3)2 and Te(SCH3)2 were investigated using gas-phase electron diffraction (GED) and ab initio and DFT geometry optimisations. While parameters involving H atoms were refined using flexible restraints according to the SARACEN method, parameters that depended only on heavy atoms could be refined without restraints. The GED-determined geometric parameters (rh1) are: rSe-S 219.1(1), rS-C 183.2(1), rC-H 109.6(4) pm; S-Se-S 102.9(3), Se-S-C 100.6(2), S-C-H (mean) 107.4(5), S-Se-S-C 87.9(20), Se-S-C-H 178.8(19)° for Se(SCH3)2, and rTe-S 238.1(2), rS-C 184.1(3), rC-H 110.0(6) pm; S-Te-S 98.9(6), Te-S-C 99.7(4), S-C-H (mean) 109.2(9), S-Te-S-C 73.0(48), Te-S-C-H 180.…

Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC

2017

MoEDAL is designed to identify new physics in the form of long-lived highly-ionising particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC run-1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges excee…

Calculation of surface quantum levels in tellurium inversion layers

1978

Evaluation of left ventricular mass on cadmium-zinc-telluride imaging: Validation against cardiac magnetic resonance

2017

Background. Single-photon emission computed tomography has shown relevant limitations in the quantification of left ventricular (LV) mass. We sought to compare the estimates of LV mass on Cadmium-Zinc-Telluride (CZT) myocardial perfusion imaging (MPI) as compared to cardiac magnetic resonance (CMR). Methods and results. Twenty-five patients underwent MPI on a CZT camera and CMR on a 1.5 T scanner within 12 ± 3 weeks. LV mass was quantified on CZT images using two softwares: 4D-MSPECT (4DM) and Emory Cardiac Toolbox (ECTb). LV mass by CMR was quantified using MASS software (Medis, Leiden, The Netherlands). LV mass values obtained with 4DM and ECTb were highly reproducible [intraclass correla…

Oxidative dehydrogenation of ethane on Te-containing MoVNbO catalysts

2004

Abstract Ethylene has selectively been obtained during the oxidative dehydrogenation of ethane on a Mo–V–Te–Nb–O mixed oxide catalyst. The catalyst was prepared hydrothermally and heat-treated at 600 °C for 2 h in a N2-stream. For comparison, undoped and Te-doped Mo–V–Nb–O catalysts and Mo–V–Te–O and Mo–Te–Nb–O mixed oxides have also been prepared. The catalytic performance of the Mo–V–Nb–Te–O mixed oxide catalyst cannot be explained by the incorporation of Te on the surface of a Mo–V–Nb–O mixed oxide but by the presence of an orthorhombic Te2M20O57 (M=Mo, V, Nb) crystalline phase. The role of tellurium in these catalysts is also discussed.

Scanning Probe Microscopy Study of the Metal-Rich Layered Chalcogenides TaM2Te2 (M = Co, Ni)

1998

The compounds TaNi2Te2 and TaCo2Te2 have been examined by scanning tunneling and atomic force microscopy. The title phases crystallize in layered structures with metal slabs sandwiched by tellurium atoms. Scanning probe microscope images of the surfaces of these materials arise from the surface tellurium atoms anddepending on the experimental conditionscan show very different features. The images have been simulated through surface charge densities calculated within the Extended Huckel and LMTO frameworks.