Researchers have shown significant interest in modulating the peroxidase-like activity of nanozymes.Among these,bimetallic nanozymes have shown superior peroxidase-like activity over monometallic counterparts,offering...Researchers have shown significant interest in modulating the peroxidase-like activity of nanozymes.Among these,bimetallic nanozymes have shown superior peroxidase-like activity over monometallic counterparts,offering enhanced performance and cost-efficiency in nanozyme designs.Herein,bimetallic nanozymes comprising nickel(Ni)and osmium(Os)incorporated into hyaluronate(HA)have been developed,resulting in HA-Nin/Os nanoclusters.Subsequently,comprehensive characterizations have been conducted.Further investigation has revealed that HA-Nin/Os efficiently catalyzed 3,3,5,5-tetramethylbenzidine(TMB)oxidation with hydrogen peroxide(H_(2)O_(2)),confirming its peroxidase-like behavior and role as a nanozyme.Impressively,HA-Ni_(2)/Os(Ni/Os=2:1)displays heightened substrate affinity,accelerated reaction rates,enhanced hydroxyl radical production in acidic conditions,and exhibits activity unit of 1224 U/mg,representing more than two-fold increase compared to non-Ni-supported Os nanozyme.Theoretical calculations indicate that Ni support enhances the peroxidase-like process of Os nanozyme by improving H_(2)O_(2) adsorption and TMB oxidation.Crucially,the support of Ni does not significantly alter the other enzyme-like activities of Os nanozymes,thereby enabling Ni to selectively enhance their peroxidase-like activity.In terms of application,the peroxidase-like ability of HA-Ni_(2)/Os,facilitated by HA's carboxyl groups enabling crosslinking,proves effective in a squamous carcinoma antigen immunoassay.Moreover,HA-Ni_(2)/Os exhibit reliable stability,promising as a peroxidase substitute.This work underscores the advantages of incorporating Ni into Os,specifically enhancing peroxidase-like activity,highlighting the potential of Os bimetallic nanozymes for peroxidase-based applications.展开更多
This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decompositio...This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decomposition of samples by means of alkali fusion, extraction of rhenium by acetone and extraction of osmium by distillation. The recovery of both elements in the entire process was more than 90% . The blanks of analyses were 0.07 ng for rhenium and 0.01 ng for 187Os. The mineralization ages of molybdenites from four molybdenum deposits in China were determined by using this method, with a precision (2σ)of about ±3% . These results agree satisfactorily with their geological backgrounds. The Re-Os method can directly determine ages of metal deposits and reflect the true ages more reliably than other dating methods that only determine the ages of country rocks from which mineralization ages are inferred. As many hydrothermal sulphide deposits usually contain molybdenites, this method has bright prospects of wide application.展开更多
This review focuses on the evolution of the use of osmium complexes as catalysts in the hydrogenation and isomerization of olefins.Osmium systems show good catalytic activities and selectivities in the hydrogenation o...This review focuses on the evolution of the use of osmium complexes as catalysts in the hydrogenation and isomerization of olefins.Osmium systems show good catalytic activities and selectivities in the hydrogenation of olefins via both dihydrogen and transfer hydrogenation.Such systems therefore have significant potential to become a powerful tool in organic synthesis.展开更多
The experiments have proved that Os(Ⅳ) has very strong catalytic effect on the chlorate oxidation of As(Ⅲ) in perchloric acid media, and As(Ⅲ) exhibits a sensitive single-sweep oscillopolarographic wave at-0.75 V v...The experiments have proved that Os(Ⅳ) has very strong catalytic effect on the chlorate oxidation of As(Ⅲ) in perchloric acid media, and As(Ⅲ) exhibits a sensitive single-sweep oscillopolarographic wave at-0.75 V vs. SCE. The kinetics of this catalytic reaction has been investigated by the initial rate procedure. The mechanism has been proposed. A new and highly sensitive catalytic reaction-oscillopolarographic method for the determination of ultratrace amounts of osmium has been described, based on the Os(Ⅳ) catalytic effect on the reaction. The linear range of 5.0×10^(-11)-4.4×10^(-9) mol/L and 6.0×10^(-9)-1.3×10^(-7) mol/L Os was obtained using the fixed-time procedure and the initial rate procedure, respectively. Osmium in refined ore was analysed by this method.展开更多
High-pressure Raman scattering from hexagonal close-packed(HCP) metals Os and Re have been extended up to 200 GPa, and the pressure-dependent shear modulus C_(44)has been deduced from the Raman-active mode E_(28), whi...High-pressure Raman scattering from hexagonal close-packed(HCP) metals Os and Re have been extended up to 200 GPa, and the pressure-dependent shear modulus C_(44)has been deduced from the Raman-active mode E_(28), which is generated from the adjacent vibration of atoms in hexagonal planes, providing the valuable information about the elastic properties for HCP metals under high pressure. Combined with the available data of HCP metals from previous works,a further study indicates that the C_(44)/C_(44)ratio would be close to a constant value, 0.01, with increasing atomic number of metals. The results obtained from high-pressure Raman scattering will allow us to probe the elastic anisotropy of the HCP metals at very high pressure.展开更多
We have performed the first-principles linear response calculations of the lattice dynamics, thermal equation of state and thermodynamical properties of hep Os metal by using the plane-wave pseudopotential method. The...We have performed the first-principles linear response calculations of the lattice dynamics, thermal equation of state and thermodynamical properties of hep Os metal by using the plane-wave pseudopotential method. The thermodynamical properties are deduced from the calculated Helmholtz free energy by taking into account the electronic contribution and lattice vibrational contribution. The phonon frequencies at Gamma point are consistent with ex- perimental values and the dispersion curves at various pressures have been determined. The calculated volume, bulk modulus and their pressure derivatives as a function of temperature are in excellent agreement with the experimental results. The calculated specific heat indicates that the electronic contribution is important not only at very low tem- peratures but also at high temperatures due to the electronic thermal excitation. The calculated Debye temperature at a very low temperature is in good agreement with experimental values and drops to a constant until 100 K.展开更多
Bis (aliphatic amine ) ruthenium (Ⅱ) and osmium (Ⅱ) porphyrins, M (Por )-(H2NR)2 andM(Por) (HNR'2)2, [M = Ru and Os; Por=meso-tetrakis (p-tolyl)porphyrinato (TTP), meso-tetrakis (4-chlorophenyl )porphyrinato (4-...Bis (aliphatic amine ) ruthenium (Ⅱ) and osmium (Ⅱ) porphyrins, M (Por )-(H2NR)2 andM(Por) (HNR'2)2, [M = Ru and Os; Por=meso-tetrakis (p-tolyl)porphyrinato (TTP), meso-tetrakis (4-chlorophenyl )porphyrinato (4-Cl-TPP ), meso-tetrakis (3, 5-dichlorophenyl) porphyrinato (3, 5-Cl-TPP ) andmeso-tetraphenyl porphyrinato(TPP); R=methyl, ethyl, iso-propyl and t-butyl; R'=methyl and ethyl]were synthesized by us. The electrochemical behavior of these complexes in 1,2-dichloroethane with TBABF4as supporting electrolyte, has been studied by cyclic voltammetry and controlled potential electrolysis. Bis(aliphatic amine)ruthenium (Ⅱ)porphyrins under go reversible one-electron oxidation and one-electron reduction processes in 1,2-dichloroethane solution. The osmium(Ⅱ) analogues is shown two oxidation couplesⅢ and Ⅴ, an additional small wave Ⅳ. The redox potentials of these complexes are markedly dependent onthe nature of the substituent bound to the phenyl group of the porphyrin ring. It is obvious that redox potentials increases the electron-withdrawing power of the substituents increases. The couple I was found at-0. 34, -0. 23 and -0. 15 V vs CP2 Fe+/o (Cp2Fe = ferrocene) for Ru (TPP ) (H2NBu-t)2, Ru (4-Cl-TPP)(H2NBu-t)2 and Ru (3, 5-Cl-TPP) (H2NBu-t)2 respectively.展开更多
Significant interest has been focused on graphene materials for their unique properties as Hydrogen storage materials. The development of their abilities by modifying their configuration with doped or decorated transi...Significant interest has been focused on graphene materials for their unique properties as Hydrogen storage materials. The development of their abilities by modifying their configuration with doped or decorated transition metals </span><span style="font-family:Verdana;">was also of great interest. In this work</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> using the DFT/B3LYP/6-31G/LanL2DZ</span><span style="font-family:Verdana;"> level of theory, graphene sheet (GS) as one of the materials of interest was doped with two transition metals, Osmium (Os) and Tungsten (W). Two active sites on the GS were tested (C4 and C16) resulted into adsorbed systems, H2@C4-GS and H2@C16-GS. C16 position showed the largest adsorption energy compared to that at C4. Therefore, C4 was replaced by the two metals and two adsorbed systems were formed</span><span style="font-family:Verdana;">: </span><span style="font-family:Verdana;">H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS and H2@W-GS. The binding energy of H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS was found to be greater than that of H2@W-GS.展开更多
Digestion with aqua regia in a Carius tube and separation of Re with anion exchange resin is commonly employed for Re–Os dating of molybdenite and pyrite.However, the recovery of Re is extremely low when this routine...Digestion with aqua regia in a Carius tube and separation of Re with anion exchange resin is commonly employed for Re–Os dating of molybdenite and pyrite.However, the recovery of Re is extremely low when this routine anion exchange method is applied to galena,causing difficulty in Re–Os dating of galena. In this study,we investigated the mechanism of Re loss during sample preparation and tested a revised procedure for Re–Os dating of galena and sphalerite.展开更多
A time resolved chemiluminescent analysis for simultaneous determination of trace Au(Ⅲ) and Os(Ⅳ) was proposed. The method is based on the kinetic distinction of Au(Ⅲ) and Os(Ⅳ) in Tween 80 KOH chemilumescent sy...A time resolved chemiluminescent analysis for simultaneous determination of trace Au(Ⅲ) and Os(Ⅳ) was proposed. The method is based on the kinetic distinction of Au(Ⅲ) and Os(Ⅳ) in Tween 80 KOH chemilumescent system. The detection limits were 1.1×10 -9 g/ml for Au(Ⅲ) and 1.0×10 -8 g/ml for Os(Ⅳ), with the linear ranges of 1.0×10 -8 ～1.0×10 -5 g/ml for Au(Ⅲ) and 1.0×10 -7 ～1.0×10 -6 g/ml for Os(Ⅳ). The method was applied to the determination of Au(Ⅲ) and Os(Ⅳ) in the sample of metallurgical materials of noble metals with satisfactory results.展开更多
A highly sensitive indirect spectrophotometric red-ox method for the determination of osmium is reported. The method is based on the oxidation of iodide by osmium （Ⅵ） and the spectrophotometric detection of the lib...A highly sensitive indirect spectrophotometric red-ox method for the determination of osmium is reported. The method is based on the oxidation of iodide by osmium （Ⅵ） and the spectrophotometric detection of the liberated iodine in the form of complex anion and ion associate with 2-（4-diethylaminostyryl）-1,3,3-trimethyl-6-nitro-3H-indolium chloride reagent. The appropriate reaction conditions have been established. The molar absorptivity is （ 1.6-5.6） × 10^4 L mol^-1 cm^-1. Beer＇s law holds for the concentration range of 0.5-11.4 μg mL^-1 of Os（Ⅵ）.展开更多
Glutathione depletion provides a promising strategy for the design of non-platinum anticancer drugs.Here we report a series of electrophilic (salen)osmium(Ⅵ) nitrides that react with glutathione to generate (salen)os...Glutathione depletion provides a promising strategy for the design of non-platinum anticancer drugs.Here we report a series of electrophilic (salen)osmium(Ⅵ) nitrides that react with glutathione to generate (salen)osmium(Ⅲ) ammine compounds.In vitro studies indicate that these osmium(VI) nitrides show comparable cytotoxicity to cisplatin against various carcinoma.Mechanistic studies with the representative compound[OsⅥ(N)(LH)(OH_(2))](PF6)(1,LH=N,N’-bis(salicylidene)-o-cyclohexyldiamine dianion) suggest that 1 induces glutathione depletion,reactive oxygen species generation,endoplasmic reticulum stress,and in turn triggers death receptor-mediated apoptosis and autophagy in lung cancer cells.In vivo evaluations show that 1 can inhibit tumor xenograft growth effectively with no body weight drop.展开更多
Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry(GDMS)and X-ray photoelectron spe...Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry(GDMS)and X-ray photoelectron spectroscopy(XPS)were used to analyze the impurity contents and distributions in the osmium target.The chemical states of impurity elements were analyzed and characterized.The total amount of metallic impurity in the target was lower than 0.01 wt%.展开更多
The reaction of Os(RL1)(PPh3)2(CO)Br, 1b, with qui-nolin-8-ol (HQ), 2, has furnished complexes of the type [Os(RL2)(PPh3)2(CO)(Q)], 3, in excellent yield (RL1 is C6H2O-2-CHNHC6H4R(p)-3-Me-5, RL2 is C6H2OH-2-CHNC6H4R(p...The reaction of Os(RL1)(PPh3)2(CO)Br, 1b, with qui-nolin-8-ol (HQ), 2, has furnished complexes of the type [Os(RL2)(PPh3)2(CO)(Q)], 3, in excellent yield (RL1 is C6H2O-2-CHNHC6H4R(p)-3-Me-5, RL2 is C6H2OH-2-CHNC6H4R(p)-3-Me-5 and R is Me, OMe, Cl). In this process, quinolin-8-olato (Q) undergoes five-membered chelation, the iminium-phenolato function tautomerizing to the imine-phenol function. The trans geometry of the Os(PPh3)2 fragment is consistent with the occurrence of a single 31P resonance near –6.0 ppm in 3. In dichloromethane solution, 3 displays a quasireversible 3+/3 couple near 0.40 V vs. SCE (3+ is the osmium (III) analogue of 3). Coulometrically generated solutions of 3+ displays a strong absorption near 340 nm, 415 nm and 500 nm and are one-electron paramagnetic (low-spin d5, S = 1/2) and show rhombic EPR spectra in 1:1 dichloromethanetoluene solution at 77 K with g values near 2.44, 2.20, 1.83. Distortion parameters using the observed g values have been computed. Solutions of 3 absorb near 420 nm and emit near 510 nm at 298 K and 580 nm at 77 K. The fluorescence is believed to originate from the 3MLCT state.展开更多
The aim of the work was the modification of a carbon nanotube paste electrode with a highly original osmium-polymer hydrogel for the development of a new amperometric biosensor for detection of sucrose and fructose. T...The aim of the work was the modification of a carbon nanotube paste electrode with a highly original osmium-polymer hydrogel for the development of a new amperometric biosensor for detection of sucrose and fructose. The biosensor for sucrose is based on the activity of the enzymes invertase and fructose dehydrogenase (FDH) immobilized into a carbon nanotube paste (CNTP) electrode properly modified with the Os-polymer. A second biosensor, for fructose only, is constructed containing inactive invertase and used for detection of fructose and for signal subtraction. The biosensors exhibit a detection limit for sucrose of 2 mM and for fructose of 1 mM, linearity up to 5 mM for both biosensors, high sensitivity (1.98 mA·cm-2·mM for sucrose and 1.95 mA·cm-2·mM for fructose), a good reproducibility (RSD = 2.5% for sucrose and 2.1% for fructose), fast response time (8 s for sucrose and 4 s for fructose) and a stability of about 4 months for both biosensors when stored under wet conditions at 4°C. Finally, the biosensors were applied for specific determination of sucrose and fructose in several commercial fruit juice samples and validated with a commercial spectrophotometric enzymatic kit.展开更多
Anchoring of unimolecular metal oxide onto appropriate supports is a promising and attractive approach for designing efficient metal–oxide-based catalysts from the perspective of economic and environmental sustainabi...Anchoring of unimolecular metal oxide onto appropriate supports is a promising and attractive approach for designing efficient metal–oxide-based catalysts from the perspective of economic and environmental sustainability.In the present paper,anchoring of osmium(Os)oxide onto silanol-functionalized polyoxometalates(POMs)to form a single-site supported Os-POM catalyst,in which the isolated osmium tetroxide was tris-grafted on a silanol-functionalized POM platform,has been studied in detail for catalytic oxidation of propylene with dioxygen by using density functional theory(DFT)calculations with the M06L functional.The results derived from the molecular geometry,electronic structure,and OsvO bonding feature for this Os-POM catalyst show that(i)rotation of the anionic center subunit of the silanolfunctionalized trilacunary POM ligand leads to a coordinated environment conversion from a tetrahedron to a trigonal bipyramid around the transition metal Os center;(ii)a detailed comparison shows that the trigonal bipyramid configuration is the most stable species and provides a large OsvO distance and(iii)possesses a matched orbital level for epoxidation of propylene to epoxypropane.The calculated free energy profiles for the epoxidation of propylene show that the rate-determining step is desorption of the first epoxypropane molecule from the Os center.Electronic structure analysis along the reaction pathway shows that the Os-POM catalyst serves as an electrophile,accepting electrons from the propyleneπbonding orbital to the π*antibonding orbital of the Os-POM catalyst to break the OsvO bond during the oxygen transfer process.Oxygen transfer to the terminal carbon atom of propylene is more favored than the bridging carbon atom because the electron-donating methyl substituent in propylene makes the terminal carbon atom more nucleophilic and accessible for the electrophilic attack by the OsvO bond.Cleavage of dioxygen on the Os-POM catalyst is a barrier free process via a quintet-to-singlet state intersystem crossing.The ability of the POM platform to accept and stabilize excess electrons from the Os center effectively promotes the oxygen transfer process,and thus is favorable for epoxidation of propylene by dioxygen.展开更多
Ruthenium and osmium complexes have been shown to bypass several resistance mechanisms of platinum anticancer drugs,suggesting that they might represent therapeutic alternatives.However,the resistance mechanisms that ...Ruthenium and osmium complexes have been shown to bypass several resistance mechanisms of platinum anticancer drugs,suggesting that they might represent therapeutic alternatives.However,the resistance mechanisms that may alter the cytotoxicity of ruthenium and osmium complexes have not been identified yet.展开更多
Upon irradiation by blue LED(λ>460 nm),the tricyano osmium nitrido complex[Os^(VI)(N)(L)(CN)_(3)]^(-)(OsN)in its excited state readily abstracts chalcogen atoms from the anions NCE^(-)(E=O,S,Se)to give the corresp...Upon irradiation by blue LED(λ>460 nm),the tricyano osmium nitrido complex[Os^(VI)(N)(L)(CN)_(3)]^(-)(OsN)in its excited state readily abstracts chalcogen atoms from the anions NCE^(-)(E=O,S,Se)to give the corresponding metal chalcogenonitrosyls[Os^(Ⅱ)(NuE)(L)(CN)_(3)]^(-)(OsNE)and CN^(-).A similar S atom abstraction also occurs in the photoreaction of OsN with organic sulfide,such as diisopropyl sulfide.展开更多
The photoreaction of an osmium(Ⅵ)nitrido complex,[OsⅥ(N)(L)(CN)_(3)]^(-)(OsN),with various phenols has been investigated.Upon irradiation of OsN with visible light,the excited state(OsN^(*))is generated which reacts...The photoreaction of an osmium(Ⅵ)nitrido complex,[OsⅥ(N)(L)(CN)_(3)]^(-)(OsN),with various phenols has been investigated.Upon irradiation of OsN with visible light,the excited state(OsN^(*))is generated which reacts readily with a variety of phenols.OsN^(*)reacts with mono-and di-substituted phenols,including 2,6-dimethylphenol,2,6-dichlorophenol and 4-methylphenol to afford the corresponding osmium(Ⅱ)benzoquinone monoimine and osmium(Ⅳ)benzoquinone monoiminato complexes.On the other hand,in the reactions of OsN^(*)with bulky tri-substituted phenol such as 2,4,6-tri-tert-butylphenol,C-C bond cleavage occurred and[OsⅣ(L)(CN)_(3)(NvtBu_(2)Ph(-2H)O)]^(-)was formed as the major product.The electronic effects of various para-substituents(X)on the oxidation of phenols were investigated by the method of initial rates(R_(x)).A Hammett plot of log(R_(x)/R_(H))versusσ_(p) is linear with aρvalue of-0.54.A linear correlation of log(R_(x))with the oxidation potentials(E)of phenols was also found with a slope of-0.80.On the other hand,no correlations were found between log(R_(x))and O-H bond dissociation energy(BDE),as well as the pKa of phenols.The oxidation of phenols by OsN^(*)exhibits a negligible kinetic isotope effect(KIE),k(C_(6)H_(5)OH)/k(C_(6)D_(5)OD)∼1.These results are consistent with a mechanism that involves an initial 1e-oxidation of the phenol followed by rapid proton transfer(ET-PT)to generate a phenoxy radical,this is followed by a N-rebound step to give the osmium products.展开更多
基金financial support from the Natural Science Foundation of Fujian Province(No.2022J01271)the Joint Funds for the Innovation of Science and Technology,Fujian Province(No.2023Y9226)+1 种基金the Introduced High-Level Talent Team Project of Quanzhou City(No.2023CT008)the Doctoral Research Foundation Project of the Second Affiliated Hospital of Fujian Medical University(No.BS202201)。
文摘Researchers have shown significant interest in modulating the peroxidase-like activity of nanozymes.Among these,bimetallic nanozymes have shown superior peroxidase-like activity over monometallic counterparts,offering enhanced performance and cost-efficiency in nanozyme designs.Herein,bimetallic nanozymes comprising nickel(Ni)and osmium(Os)incorporated into hyaluronate(HA)have been developed,resulting in HA-Nin/Os nanoclusters.Subsequently,comprehensive characterizations have been conducted.Further investigation has revealed that HA-Nin/Os efficiently catalyzed 3,3,5,5-tetramethylbenzidine(TMB)oxidation with hydrogen peroxide(H_(2)O_(2)),confirming its peroxidase-like behavior and role as a nanozyme.Impressively,HA-Ni_(2)/Os(Ni/Os=2:1)displays heightened substrate affinity,accelerated reaction rates,enhanced hydroxyl radical production in acidic conditions,and exhibits activity unit of 1224 U/mg,representing more than two-fold increase compared to non-Ni-supported Os nanozyme.Theoretical calculations indicate that Ni support enhances the peroxidase-like process of Os nanozyme by improving H_(2)O_(2) adsorption and TMB oxidation.Crucially,the support of Ni does not significantly alter the other enzyme-like activities of Os nanozymes,thereby enabling Ni to selectively enhance their peroxidase-like activity.In terms of application,the peroxidase-like ability of HA-Ni_(2)/Os,facilitated by HA's carboxyl groups enabling crosslinking,proves effective in a squamous carcinoma antigen immunoassay.Moreover,HA-Ni_(2)/Os exhibit reliable stability,promising as a peroxidase substitute.This work underscores the advantages of incorporating Ni into Os,specifically enhancing peroxidase-like activity,highlighting the potential of Os bimetallic nanozymes for peroxidase-based applications.
基金This research was supported jointly by the Foundation for Development of Geological Science and Technology (Project No. 49173164)
文摘This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decomposition of samples by means of alkali fusion, extraction of rhenium by acetone and extraction of osmium by distillation. The recovery of both elements in the entire process was more than 90% . The blanks of analyses were 0.07 ng for rhenium and 0.01 ng for 187Os. The mineralization ages of molybdenites from four molybdenum deposits in China were determined by using this method, with a precision (2σ)of about ±3% . These results agree satisfactorily with their geological backgrounds. The Re-Os method can directly determine ages of metal deposits and reflect the true ages more reliably than other dating methods that only determine the ages of country rocks from which mineralization ages are inferred. As many hydrothermal sulphide deposits usually contain molybdenites, this method has bright prospects of wide application.
文摘This review focuses on the evolution of the use of osmium complexes as catalysts in the hydrogenation and isomerization of olefins.Osmium systems show good catalytic activities and selectivities in the hydrogenation of olefins via both dihydrogen and transfer hydrogenation.Such systems therefore have significant potential to become a powerful tool in organic synthesis.
文摘The experiments have proved that Os(Ⅳ) has very strong catalytic effect on the chlorate oxidation of As(Ⅲ) in perchloric acid media, and As(Ⅲ) exhibits a sensitive single-sweep oscillopolarographic wave at-0.75 V vs. SCE. The kinetics of this catalytic reaction has been investigated by the initial rate procedure. The mechanism has been proposed. A new and highly sensitive catalytic reaction-oscillopolarographic method for the determination of ultratrace amounts of osmium has been described, based on the Os(Ⅳ) catalytic effect on the reaction. The linear range of 5.0×10^(-11)-4.4×10^(-9) mol/L and 6.0×10^(-9)-1.3×10^(-7) mol/L Os was obtained using the fixed-time procedure and the initial rate procedure, respectively. Osmium in refined ore was analysed by this method.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 11774247 and U2030107)Sichuan University Innovation Research Program of China (Grant No. 2020SCUNL107)。
文摘High-pressure Raman scattering from hexagonal close-packed(HCP) metals Os and Re have been extended up to 200 GPa, and the pressure-dependent shear modulus C_(44)has been deduced from the Raman-active mode E_(28), which is generated from the adjacent vibration of atoms in hexagonal planes, providing the valuable information about the elastic properties for HCP metals under high pressure. Combined with the available data of HCP metals from previous works,a further study indicates that the C_(44)/C_(44)ratio would be close to a constant value, 0.01, with increasing atomic number of metals. The results obtained from high-pressure Raman scattering will allow us to probe the elastic anisotropy of the HCP metals at very high pressure.
基金supported by National Natural Science Associated Foundation (NSAF) of China (Grant No. 10776024)the Programfor Young Excellent Talents in Tongji University
文摘We have performed the first-principles linear response calculations of the lattice dynamics, thermal equation of state and thermodynamical properties of hep Os metal by using the plane-wave pseudopotential method. The thermodynamical properties are deduced from the calculated Helmholtz free energy by taking into account the electronic contribution and lattice vibrational contribution. The phonon frequencies at Gamma point are consistent with ex- perimental values and the dispersion curves at various pressures have been determined. The calculated volume, bulk modulus and their pressure derivatives as a function of temperature are in excellent agreement with the experimental results. The calculated specific heat indicates that the electronic contribution is important not only at very low tem- peratures but also at high temperatures due to the electronic thermal excitation. The calculated Debye temperature at a very low temperature is in good agreement with experimental values and drops to a constant until 100 K.
文摘Bis (aliphatic amine ) ruthenium (Ⅱ) and osmium (Ⅱ) porphyrins, M (Por )-(H2NR)2 andM(Por) (HNR'2)2, [M = Ru and Os; Por=meso-tetrakis (p-tolyl)porphyrinato (TTP), meso-tetrakis (4-chlorophenyl )porphyrinato (4-Cl-TPP ), meso-tetrakis (3, 5-dichlorophenyl) porphyrinato (3, 5-Cl-TPP ) andmeso-tetraphenyl porphyrinato(TPP); R=methyl, ethyl, iso-propyl and t-butyl; R'=methyl and ethyl]were synthesized by us. The electrochemical behavior of these complexes in 1,2-dichloroethane with TBABF4as supporting electrolyte, has been studied by cyclic voltammetry and controlled potential electrolysis. Bis(aliphatic amine)ruthenium (Ⅱ)porphyrins under go reversible one-electron oxidation and one-electron reduction processes in 1,2-dichloroethane solution. The osmium(Ⅱ) analogues is shown two oxidation couplesⅢ and Ⅴ, an additional small wave Ⅳ. The redox potentials of these complexes are markedly dependent onthe nature of the substituent bound to the phenyl group of the porphyrin ring. It is obvious that redox potentials increases the electron-withdrawing power of the substituents increases. The couple I was found at-0. 34, -0. 23 and -0. 15 V vs CP2 Fe+/o (Cp2Fe = ferrocene) for Ru (TPP ) (H2NBu-t)2, Ru (4-Cl-TPP)(H2NBu-t)2 and Ru (3, 5-Cl-TPP) (H2NBu-t)2 respectively.
文摘Significant interest has been focused on graphene materials for their unique properties as Hydrogen storage materials. The development of their abilities by modifying their configuration with doped or decorated transition metals </span><span style="font-family:Verdana;">was also of great interest. In this work</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> using the DFT/B3LYP/6-31G/LanL2DZ</span><span style="font-family:Verdana;"> level of theory, graphene sheet (GS) as one of the materials of interest was doped with two transition metals, Osmium (Os) and Tungsten (W). Two active sites on the GS were tested (C4 and C16) resulted into adsorbed systems, H2@C4-GS and H2@C16-GS. C16 position showed the largest adsorption energy compared to that at C4. Therefore, C4 was replaced by the two metals and two adsorbed systems were formed</span><span style="font-family:Verdana;">: </span><span style="font-family:Verdana;">H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS and H2@W-GS. The binding energy of H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS was found to be greater than that of H2@W-GS.
基金supported by the 12th Five-Year Plan Project of State Key Laboratory of Ore Deposit Geochemistry, Chinese Academy of Sciences (SKLODG-ZY125-09 SKLODGZY125-02)+1 种基金the National Natural Science Foundation of China (Nos. 41373064 41430315)
文摘Digestion with aqua regia in a Carius tube and separation of Re with anion exchange resin is commonly employed for Re–Os dating of molybdenite and pyrite.However, the recovery of Re is extremely low when this routine anion exchange method is applied to galena,causing difficulty in Re–Os dating of galena. In this study,we investigated the mechanism of Re loss during sample preparation and tested a revised procedure for Re–Os dating of galena and sphalerite.
文摘A time resolved chemiluminescent analysis for simultaneous determination of trace Au(Ⅲ) and Os(Ⅳ) was proposed. The method is based on the kinetic distinction of Au(Ⅲ) and Os(Ⅳ) in Tween 80 KOH chemilumescent system. The detection limits were 1.1×10 -9 g/ml for Au(Ⅲ) and 1.0×10 -8 g/ml for Os(Ⅳ), with the linear ranges of 1.0×10 -8 ～1.0×10 -5 g/ml for Au(Ⅲ) and 1.0×10 -7 ～1.0×10 -6 g/ml for Os(Ⅳ). The method was applied to the determination of Au(Ⅲ) and Os(Ⅳ) in the sample of metallurgical materials of noble metals with satisfactory results.
文摘A highly sensitive indirect spectrophotometric red-ox method for the determination of osmium is reported. The method is based on the oxidation of iodide by osmium （Ⅵ） and the spectrophotometric detection of the liberated iodine in the form of complex anion and ion associate with 2-（4-diethylaminostyryl）-1,3,3-trimethyl-6-nitro-3H-indolium chloride reagent. The appropriate reaction conditions have been established. The molar absorptivity is （ 1.6-5.6） × 10^4 L mol^-1 cm^-1. Beer＇s law holds for the concentration range of 0.5-11.4 μg mL^-1 of Os（Ⅵ）.
基金financially supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302009)the National Natural Science Foundation of China(No.21401125)+3 种基金the Li Ka Shing Foundation Cross-Disciplinary Research Grant(No.2020LKSFG01F)Research Grants Council of Hong Kong(No.HKBU 12300121)Hong Kong Baptist University for the start-up fund(No.RC-OFSGT2/20-21/SCI/008)supported by"Laboratory for Synthetic Chemistry and Chemical Biology"under the Health@Inno HK Program launched by Innovation and Technology Commission,The Government of Hong Kong Special Administrative Region of the People’s Republic of China。
文摘Glutathione depletion provides a promising strategy for the design of non-platinum anticancer drugs.Here we report a series of electrophilic (salen)osmium(Ⅵ) nitrides that react with glutathione to generate (salen)osmium(Ⅲ) ammine compounds.In vitro studies indicate that these osmium(VI) nitrides show comparable cytotoxicity to cisplatin against various carcinoma.Mechanistic studies with the representative compound[OsⅥ(N)(LH)(OH_(2))](PF6)(1,LH=N,N’-bis(salicylidene)-o-cyclohexyldiamine dianion) suggest that 1 induces glutathione depletion,reactive oxygen species generation,endoplasmic reticulum stress,and in turn triggers death receptor-mediated apoptosis and autophagy in lung cancer cells.In vivo evaluations show that 1 can inhibit tumor xenograft growth effectively with no body weight drop.
基金financially supported by the Key R&D Program of Ministry of Science and Technology(No.2017YFB0305400)。
文摘Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry(GDMS)and X-ray photoelectron spectroscopy(XPS)were used to analyze the impurity contents and distributions in the osmium target.The chemical states of impurity elements were analyzed and characterized.The total amount of metallic impurity in the target was lower than 0.01 wt%.
文摘The reaction of Os(RL1)(PPh3)2(CO)Br, 1b, with qui-nolin-8-ol (HQ), 2, has furnished complexes of the type [Os(RL2)(PPh3)2(CO)(Q)], 3, in excellent yield (RL1 is C6H2O-2-CHNHC6H4R(p)-3-Me-5, RL2 is C6H2OH-2-CHNC6H4R(p)-3-Me-5 and R is Me, OMe, Cl). In this process, quinolin-8-olato (Q) undergoes five-membered chelation, the iminium-phenolato function tautomerizing to the imine-phenol function. The trans geometry of the Os(PPh3)2 fragment is consistent with the occurrence of a single 31P resonance near –6.0 ppm in 3. In dichloromethane solution, 3 displays a quasireversible 3+/3 couple near 0.40 V vs. SCE (3+ is the osmium (III) analogue of 3). Coulometrically generated solutions of 3+ displays a strong absorption near 340 nm, 415 nm and 500 nm and are one-electron paramagnetic (low-spin d5, S = 1/2) and show rhombic EPR spectra in 1:1 dichloromethanetoluene solution at 77 K with g values near 2.44, 2.20, 1.83. Distortion parameters using the observed g values have been computed. Solutions of 3 absorb near 420 nm and emit near 510 nm at 298 K and 580 nm at 77 K. The fluorescence is believed to originate from the 3MLCT state.
文摘The aim of the work was the modification of a carbon nanotube paste electrode with a highly original osmium-polymer hydrogel for the development of a new amperometric biosensor for detection of sucrose and fructose. The biosensor for sucrose is based on the activity of the enzymes invertase and fructose dehydrogenase (FDH) immobilized into a carbon nanotube paste (CNTP) electrode properly modified with the Os-polymer. A second biosensor, for fructose only, is constructed containing inactive invertase and used for detection of fructose and for signal subtraction. The biosensors exhibit a detection limit for sucrose of 2 mM and for fructose of 1 mM, linearity up to 5 mM for both biosensors, high sensitivity (1.98 mA·cm-2·mM for sucrose and 1.95 mA·cm-2·mM for fructose), a good reproducibility (RSD = 2.5% for sucrose and 2.1% for fructose), fast response time (8 s for sucrose and 4 s for fructose) and a stability of about 4 months for both biosensors when stored under wet conditions at 4°C. Finally, the biosensors were applied for specific determination of sucrose and fructose in several commercial fruit juice samples and validated with a commercial spectrophotometric enzymatic kit.
基金the National Natural Science Foundation of China(21373043).
文摘Anchoring of unimolecular metal oxide onto appropriate supports is a promising and attractive approach for designing efficient metal–oxide-based catalysts from the perspective of economic and environmental sustainability.In the present paper,anchoring of osmium(Os)oxide onto silanol-functionalized polyoxometalates(POMs)to form a single-site supported Os-POM catalyst,in which the isolated osmium tetroxide was tris-grafted on a silanol-functionalized POM platform,has been studied in detail for catalytic oxidation of propylene with dioxygen by using density functional theory(DFT)calculations with the M06L functional.The results derived from the molecular geometry,electronic structure,and OsvO bonding feature for this Os-POM catalyst show that(i)rotation of the anionic center subunit of the silanolfunctionalized trilacunary POM ligand leads to a coordinated environment conversion from a tetrahedron to a trigonal bipyramid around the transition metal Os center;(ii)a detailed comparison shows that the trigonal bipyramid configuration is the most stable species and provides a large OsvO distance and(iii)possesses a matched orbital level for epoxidation of propylene to epoxypropane.The calculated free energy profiles for the epoxidation of propylene show that the rate-determining step is desorption of the first epoxypropane molecule from the Os center.Electronic structure analysis along the reaction pathway shows that the Os-POM catalyst serves as an electrophile,accepting electrons from the propyleneπbonding orbital to the π*antibonding orbital of the Os-POM catalyst to break the OsvO bond during the oxygen transfer process.Oxygen transfer to the terminal carbon atom of propylene is more favored than the bridging carbon atom because the electron-donating methyl substituent in propylene makes the terminal carbon atom more nucleophilic and accessible for the electrophilic attack by the OsvO bond.Cleavage of dioxygen on the Os-POM catalyst is a barrier free process via a quintet-to-singlet state intersystem crossing.The ability of the POM platform to accept and stabilize excess electrons from the Os center effectively promotes the oxygen transfer process,and thus is favorable for epoxidation of propylene by dioxygen.
文摘Ruthenium and osmium complexes have been shown to bypass several resistance mechanisms of platinum anticancer drugs,suggesting that they might represent therapeutic alternatives.However,the resistance mechanisms that may alter the cytotoxicity of ruthenium and osmium complexes have not been identified yet.
基金supported by the National Natural Science Foundation of China(21771026)the Excellent Discipline Cultivation Project by JHUN(2023XKZ038)+1 种基金the Natural Science Foundation of Jingzhou Science and Technology Bureau(2022CC54-05)“Laboratory for Synthetic Chemistry and Chemical Biology”under the Health@InnoHK Program launched by Innovation and Technology Commission,The Government of Hong Kong Special Administrative Region of the People’s Republic of China.KCL and TCL also acknowledge financial support from a NSFC_RGC Joint Research Scheme(N_CityU111/20)。
文摘Upon irradiation by blue LED(λ>460 nm),the tricyano osmium nitrido complex[Os^(VI)(N)(L)(CN)_(3)]^(-)(OsN)in its excited state readily abstracts chalcogen atoms from the anions NCE^(-)(E=O,S,Se)to give the corresponding metal chalcogenonitrosyls[Os^(Ⅱ)(NuE)(L)(CN)_(3)]^(-)(OsNE)and CN^(-).A similar S atom abstraction also occurs in the photoreaction of OsN with organic sulfide,such as diisopropyl sulfide.
基金supported by the National Natural Science Foundation of China(22371092)the Excellent Discipline Cultivation Project by JHUN(2023XKZ038)+1 种基金the Project of Hebei Key Laboratory of Heterocyclic Compounds(no.KF202402)the Graduate Scientific Research Foundation of Jianghan University(KYCXJJ202426).
文摘The photoreaction of an osmium(Ⅵ)nitrido complex,[OsⅥ(N)(L)(CN)_(3)]^(-)(OsN),with various phenols has been investigated.Upon irradiation of OsN with visible light,the excited state(OsN^(*))is generated which reacts readily with a variety of phenols.OsN^(*)reacts with mono-and di-substituted phenols,including 2,6-dimethylphenol,2,6-dichlorophenol and 4-methylphenol to afford the corresponding osmium(Ⅱ)benzoquinone monoimine and osmium(Ⅳ)benzoquinone monoiminato complexes.On the other hand,in the reactions of OsN^(*)with bulky tri-substituted phenol such as 2,4,6-tri-tert-butylphenol,C-C bond cleavage occurred and[OsⅣ(L)(CN)_(3)(NvtBu_(2)Ph(-2H)O)]^(-)was formed as the major product.The electronic effects of various para-substituents(X)on the oxidation of phenols were investigated by the method of initial rates(R_(x)).A Hammett plot of log(R_(x)/R_(H))versusσ_(p) is linear with aρvalue of-0.54.A linear correlation of log(R_(x))with the oxidation potentials(E)of phenols was also found with a slope of-0.80.On the other hand,no correlations were found between log(R_(x))and O-H bond dissociation energy(BDE),as well as the pKa of phenols.The oxidation of phenols by OsN^(*)exhibits a negligible kinetic isotope effect(KIE),k(C_(6)H_(5)OH)/k(C_(6)D_(5)OD)∼1.These results are consistent with a mechanism that involves an initial 1e-oxidation of the phenol followed by rapid proton transfer(ET-PT)to generate a phenoxy radical,this is followed by a N-rebound step to give the osmium products.
