Search results for "Osmium"
showing 10 items of 35 documents
Atomic Layer Deposition of Osmium
2011
Growth of osmium thin films and nanoparticles by atomic layer deposition is described. The Os thin films were successfully grown between 325 and 375 °C using osmocene and molecular oxygen as precursors. The films consisted of only Os metal as osmium oxides were not detected in X-ray diffraction measurements. Also the impurity contents of oxygen, carbon, and hydrogen were less than 1 at % each at all deposition temperatures. The long nucleation delay of the Os process facilitates either Os nanoparticle or thin film deposition. However, after the nucleation delay of about 350 cycles the film growth proceeded linearly with increasing number of deposition cycles. Also conformal growth of Os thi…
Luminescent osmium(II) bi-1,2,3-triazol-4-yl complexes: photophysical characterisation and application in light-emitting electrochemical cells
2016
The series of osmium(II) complexes [Os(bpy)3-n(btz)n][PF6]2 (bpy = 2,2’-bipyridyl, btz = 1,1’-dibenzyl-4,4’-bi-1,2,3-triazolyl, 1 n = 0, 2 n = 1, 3 n = 2, 4 n = 3), have been prepared and characterised. The progressive replacement of bpy by btz leads to blue-shifted UV-visible electronic absorption spectra, indicative of btz perturbation of the successively destabilised bpy-centred LUMO. For 4, a dramatic blue-shift relative to the absorption profile for 3 is observed, indicative of the much higher energy LUMO of the btz ligand over that of bpy, mirroring previously reported data on analogous ruthenium(II) complexes. Unlike the previously reported ruthenium systems, heteroleptic complexes 2…
High-resolution stimulated Raman spectroscopy and analysis of the ν 1 band of osmium tetroxide
2012
D.B.P. and R.Z.M. acknowledge the financial support of the Ministry of Science and Innovation through research grant no. FIS2009-08069.
FT-ICR MS studies of ion-molecule reactions of Ru+ and Os+ with oxygen
2005
Abstract The reactions of stored ruthenium and osmium cations with oxygen have been studied in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. In case of osmium the reaction products OsO+ and OsO 2 + have been observed and corresponding reaction-rate constants have been determined. In addition, there is an unreactive fraction of Os+ ions due to the presence of a slightly endothermic reacting ground state. Only the excited states react with oxygen. For ruthenium no spontaneous reaction with oxygen has been observed unless the cyclotron motion of Ru+ was excited. The results are discussed with respect to a similar investigation in a Penning trap-TOF mass spectrometer […
BODIPY-phosphane as a versatile tool for easy access to new metal-based theranostics
2012
A new BODIPY-phosphane was synthesized and proved to be a versatile tool for imaging organometallic complexes. It also led to easy access to a new family of theranostics, featuring gold, ruthenium and osmium complexes. The compounds' cytotoxicity was tested on cancer cells, and their cell uptake was followed by fluorescence microscopy in vitro.
Synthesis and properties of dinuclear Ru(II)/Os(II) complexes based on a heteroditopic phenanthroline-terpyridine bridging ligand.
2010
The synthesis and characterization of a series of mono- and dinuclear ruthenium(II) and osmium(II) polypyridyl complexes based on the heteroditopic bridging ligand PT are reported. This ligand incorporates bidentate phen (1,10-phenanthroline) and terdentate tpy (2,2':6',2''-terpyridine) units directly connected by their 3 and 5 positions, respectively. The dinuclear complexes have been synthesized via a Pd(0) catalyzed cross-coupling reaction between a bromo-substituted Ru-phen complex and a tpy derivative incorporating a boronate ester, followed by Ru(II) or Os(II) complexation. The compounds obtained are fully characterized using spectroscopic and electrochemical measurements. The electro…
Thermal equation of state of ruthenium characterized by resistively heated diamond anvil cell
2019
AbstractThe high-pressure and high-temperature structural and chemical stability of ruthenium has been investigated via synchrotron X-ray diffraction using a resistively heated diamond anvil cell. In the present experiment, ruthenium remains stable in the hcp phase up to 150 GPa and 960 K. The thermal equation of state has been determined based upon the data collected following four different isotherms. A quasi-hydrostatic equation of state at ambient temperature has also been characterized up to 150 GPa. The measured equation of state and structural parameters have been compared to the results of ab initio simulations performed with several exchange-correlation functionals. The agreement b…
Electro- and Photo-driven Reduction of CO 2 by a trans -(Cl)-[Os(diimine)(CO) 2 Cl 2 ] Precursor Catalyst: Influence of the Diimine Substituent and A…
2016
A series of [OsII(NN)(CO)2Cl2] complexes where NN is a 2,2′-bipyridine ligand substituted in the 4,4′ positions by H (C1), CH3 (C2), C(CH3)3 (C3), or C(O)OCH(CH3)2 (C4) has been studied as catalysts for the reduction of CO2. Electrocatalysis shows that the selectivity of the reaction can be switched toward the production of CO or HCOO− with an electron-donating (C2, C3) or -withdrawing (C4) substituent, respectively. The electrocatalytic process is a result of the formation of an Os0-bonded polymer, which was characterized by electrochemistry, UV/Visible and EPR spectroscopies. Photolysis of the complexes under CO2 in DMF+TEOA produces CO as a major product with a remarkably stable turnover…
Osmium and lithium isotope evidence for weathering feedbacks linked to orbitally paced organic carbon burial and Silurian glaciations
2022
Abstract The Ordovician (∼487 to 443 Ma) ended with the formation of extensive Southern Hemisphere ice sheets, known as the Hirnantian glaciation, and the second largest mass extinction in Earth History. It was followed by the Silurian (∼443 to 419 Ma), one of the most climatically unstable periods of the Phanerozoic as evidenced by several large scale ( > 5 ‰ ) carbon isotope (δ13C) perturbations associated with further extinction events. Despite several decades of research, the cause of these environmental instabilities remains enigmatic. Here, we provide osmium (187Os/188Os) and lithium (δ7Li) isotope measurements of marine sedimentary rocks that cover four Silurian δ13C excursions. Osmi…
Laboratory phase‐contrast nanotomography of unstained Bombus terrestris compound eyes
2021
Imaging the visual systems of bumblebees and other pollinating insects may increase understanding of their dependence on specific habitats and how they will be affected by climate change. Current high-resolution imaging methods are either limited to two dimensions (light- and electron microscopy) or have limited access (synchrotron radiation x-ray tomography). For x-ray imaging, heavy metal stains are often used to increase contrast. Here, we present micron-resolution imaging of compound eyes of buff-tailed bumblebees (Bombus terrestris) using a table-top x-ray nanotomography (nano-CT) system. By propagation-based phase-contrast imaging, the use of stains was avoided and the microanatomy co…