- Nature of the Short Rh-Li Contact between Lithium and the Rhodium ω-Alkenyl Complex [Rh(CH2CMe2CH2CH═CH2)2]-
-
We describe the preparation of the cis-bis(η1,η2-2,2-dimethylpent-4-en-1-yl)rhodate(I) anion, cis-[Rh(CH2CMe2CH2CH═CH2)2]-, and the interaction of this species with Li+ both in solution and in the solid state. For the lithium(diethyl ether) salt [Li(Et2O)][Rh(CH2CMe2CH2CH═CH2)2], VT-NMR and 1H{7Li} NOE NMR studies in toluene-d8 show that the Li+ cation is in close proximity to the dz2 orbital of rhodium. In the solid-state structure of the lithium(12-crown-4) salt [Li(12-crown-4)2][Li{Rh(CH2CMe2CH2CH═CH2)2}2], one lithium atom is surrounded by two [Rh(CH2CMe2CH2CH═CH2)2]- anions, and in this assembly there are two unusually short Rh-Li distances of 2.48 ?. DFT calculations, natural energy decomposition, and ETS-NOCV analysis suggest that there is a weak dative interaction between the 4dz2 orbitals on the Rh centers and the 2pz orbital of the Li+ cation. The charge-transfer term between Rh and Li+ contributes only about the 1/5 of the total interaction energy, however, and the principal driving force for the proximity of Rh and Li in compounds 1 and 2 is that Li+ is electrostatically attracted to negative charges on the dialkylrhodiate anions.
- Liu, Sumeng,Smith, Brett A.,Kirkland, Justin K.,Vogiatzis, Konstantinos D.,Girolami, Gregory S.
-
p. 8790 - 8801
(2021/06/28)
-
- Scalable Synthesis of Esp and Rhodium(II) Carboxylates from Acetylacetone and RhCl3· xH2O
-
Rhodium(II) carboxylates are privileged catalysts for the most challenging carbene-, nitrene-, and oxo-transfer reactions. In this work, we address the strategic challenges of current organic and inorganic synthesis methods to access these rhodium(II) complexes through an oxidative rearrangement strategy and a reductive ligation reaction. These studies illustrate the multiple benefits of oxidative rearrangement in the process-scale synthesis of congested carboxylates over nitrile anion alkylation reactions, and the impressive effect of inorganic additives in the reductive ligation of rhodium(III) salts.
- Martínez-Castro, Elisa,Mendoza, Abraham,Suárez-Pantiga, Samuel
-
p. 1207 - 1212
(2020/07/15)
-
- Rational Synthesis for a Noble Metal Carbide
-
Transition metal carbides have attractive physical and chemical properties that are much different from their parent metals. Particularly, noble metal carbides are expected to be promising materials for a variety of applications, particularly as efficient catalysts. However, noble metal carbides have rarely been obtained because carbide phases do not appear in noble metal-carbon phase diagrams and a reasonable synthesis method to make noble metal carbides has not yet been established. Here, we propose a new synthesis method for noble metal carbides and describe the first synthesis of rhodium carbide using tetracyanoethylene (TCNE). The rhodium carbide was synthesized without extreme conditions, such as the very high temperature and/or pressure typically required in conventional carbide syntheses. Moreover, we investigated the electronic structure and catalytic activity for the hydrogen evolution reaction (HER). We found that rhodium carbide has much higher catalytic activity for HER than pure Rh. Our study provides a feasible strategy to create new metal carbides to help advance the field of materials science.
- Wakisaka, Takuo,Kusada, Kohei,Wu, Dongshuang,Yamamoto, Tomokazu,Toriyama, Takaaki,Matsumura, Syo,Akiba, Hiroshi,Yamamuro, Osamu,Ikeda, Kazutaka,Otomo, Toshiya,Palina, Natalia,Chen, Yanna,Kumara, Loku S. R.,Song, Chulho,Sakata, Osami,Xie, Wei,Koyama, Michihisa,Kubota, Yoshiki,Kawaguchi, Shogo,Arevalo, Ryan L.,Aspera, Susan M.,Arguelles, Elvis F.,Nakanishi, Hiroshi,Kitagawa, Hiroshi
-
p. 1247 - 1253
(2019/12/04)
-
- Anti-hepatocellular carcinoma, antioxidant, anti-inflammation and antimicrobial investigation of some novel first and second transition metal complexes
-
New coordination compounds of some selected metal ions from the first and second transition metals series with a Schiff base were synthesized and characterized. The Schiff base is derived from 4-Aminoantipyrine and 3-(hydroxyimino) butan-2-one. The compounds were characterized by different analysis tools like; elemental analysis, mass spectra, Fourier transform infrared (FTIR) as well as electronic spectra, magnetic measurements, molar conductance and thermal analysis technique. All complexes were formed with 1:1 (metal: ligand) stoichiometry except Mn (II) where 1:2 (Mn: ligand) is formed. Schiff base ligand interacted as a tridentate ligand by using the nitrogen atoms of the imine and the oximato groups and the carbonyl oxygen atom as donor groups with all studied metal ions except copper (II) and manganese (II) where the carbonyl oxygen is not shared in the coordination. These complexes show various physicochemical properties. X-ray powder diffraction shows different crystal systems; Cd (II) complex: hexagonal, Cu (II) complex: orthorhombic; and [Ni (II), Mn (II), Rh (III) & Pd (II)] complexes: monoclinic. All compounds showed potent cytotoxicity against the growth of human liver cancer cell lines. The square planar Pd (II) complex was more active than those of octahedral geometries of all other synthesized complexes. Cd (II) complex has the highest microbial growth inhibition than the rest of the prepared complexes. The docking active sites interactions were evaluated using the selected proteins EGFR tyrosine kinase and protein crystal structure of GlcN-O-P synthase. in vitro antioxidant assay revealed potent free radical scavenging activity of the three synthesized Cu (II), Pd (II) and Rh (III) complexes that exceeded the standard ascorbic acid. Pd (II) complex shows the most significant inhibition denaturation percent.
- Hassan, Safaa S.,Khalf-Alla, Perihan A.
-
-
- Ice Melting to Release Reactants in Solution Syntheses
-
Aqueous solution syntheses are mostly based on mixing two solutions with different reactants. It is shown that freezing one solution and melting it in another solution provides a new interesting strategy to mix chemicals and to significantly change the reaction kinetics and thermodynamics. For example, a precursor solution containing a certain concentration of AgNO3 was frozen and dropped into a reductive NaBH4 solution at about 0 °C. The ultra-slow release of reactants was successfully achieved. An ice-melting process can be used to synthesize atomically dispersed metals, including cobalt, nickel, copper, rhodium, ruthenium, palladium, silver, osmium, iridium, platinum, and gold, which can be easily extended to other solution syntheses (such as precipitation, hydrolysis, and displacement reactions) and provide a generalized method to redesign the interphase reaction kinetics and ion diffusion in wet chemistry.
- Wei, Hehe,Huang, Kai,Zhang, Le,Ge, Binghui,Wang, Dong,Lang, Jialiang,Ma, Jingyuan,Wang, Da,Zhang, Shuai,Li, Qunyang,Zhang, Ruoyu,Hussain, Naveed,Lei, Ming,Liu, Li-Min,Wu, Hui
-
supporting information
p. 3354 - 3359
(2018/02/21)
-
- Synthesis of a Cu-Filled Rh17S15 Framework: Microwave Polyol Process Versus High-Temperature Route
-
Metal-rich, mixed copper-rhodium sulfide Cu3-δRh34S30 that represents a new Cu-filled variant of the Rh17S15 structure has been synthesized and structurally characterized. Copper content in the [CuRh8] cubic cluster was found to vary notably dependent on the chosen synthetic route. Full site occupancy was achieved only in nanoscaled Cu3Rh34S30 obtained by a rapid, microwave-assisted reaction of CuCl, Rh2(CH3CO2)4 and thiosemicarbazide at 300 °C in just 30 min; whereas merely Cu-deficient Cu3-δRh34S30 (2.0 ≥ δ ≥ 0.9) compositions were realized via conventional high-temperature ceramic synthesis from the elements at 950 °C. Although Cu3-δRh34S30 is metallic just like Rh17S15, the slightly enhanced metal content has a dramatic effect on the electronic properties. Whereas the Rh17S15 host undergoes a superconducting transition at 5.4 K, no signs of the latter were found for the Cu-derivatives at least down to 1.8 K. This finding is corroborated by the strongly reduced density of states at the Fermi level of the ternary sulfide and the disruption of long-range Rh-Rh interactions in favor of Cu-Rh interactions as revealed by quantum-chemical calculations.
- Roslova, Maria,Golub, Pavlo,Opherden, Lars,Ovchinnikov, Alexander,Uhlarz, Marc,Baranov, Alexey I.,Prots, Yurii,Isaeva, Anna,Coduri, Mauro,Herrmannsd?rfer, Thomas,Wosnitza, Joachim,Doert, Thomas,Ruck, Michael
-
p. 11513 - 11523
(2017/10/10)
-
- Evaluation of the mechanism of heterogeneous hydrogenation of α,β-unsaturated carbonyl compounds via pairwise hydrogen addition
-
Heterogeneous hydrogenation of α,β-unsaturated carbonyl compounds was addressed using the parahydrogen-induced polarization (PHIP) technique. PHIP effects were observed in hydrogenation of C = C bond of acrolein and crotonaldehyde over different supported metal catalysts, demonstrating the existence of a pairwise route of hydrogen addition to the substrate. Hydrogenation of acrolein over Pd-Sn/Al2O3, Pd-Sn/TiO 2, Pd-Zn/TiO2, and Pd/TiO2 catalysts with parahydrogen also led to the polarization of the proton of CHO group of propanal. This was explained by C(O)-H bond dissociation which represents a side process on the catalyst surface. Formation of polarized cis- and trans-2-butenes was detected in hydrogenation of acrolein with parahydrogen over several Rh-based catalysts. This observation is made possible only due to the high NMR signal enhancement provided by PHIP. It was also found that hydrogenation of acetone and propanal with parahydrogen leads to polarized propane formation as a result of C-O bond hydrogenolysis.
- Salnikov, Oleg G.,Kovtunov, Kirill V.,Barskiy, Danila A.,Khudorozhkov, Alexander K.,Inozemtseva, Elizaveta A.,Prosvirin, Igor P.,Bukhtiyarov, Valery I.,Koptyug, Igor V.
-
p. 2022 - 2028
(2014/06/24)
-
- A series of NiM (M = Ru, Rh, and Pd) bimetallic catalysts for effective lignin hydrogenolysis in water
-
In this paper, NiRu, NiRh, and NiPd catalysts were synthesized and evaluated in the hydrogenolysis of lignin C-O bonds, which is proved to be superior over single-component catalysts. The optimized NiRu catalyst contains 85% Ni and 15% Ru, composed of Ni surface-enriched, Ru-Ni atomically mixed, ultrasmall nanoparticles. The Ni85Ru15 catalyst showed high activity under low temperature (100°C), low H2 pressure (1 bar) in β-O-4 type C-O bond hydrogenolysis. It also exhibited significantly higher activity over Ni and Ru catalysts in the direct conversion of lignin into monomeric aromatic chemicals. Mechanistic investigation indicates that the synergistic effect of NiRu can be attributed to three factors: (1) increased fraction of surface atoms (compared with Ni), (2) enhanced H2 and substrate activation (compared with Ni), and (3) inhibited benzene ring hydrogenation (compared with Ru). Similarly, NiRh and NiPd catalysts were more active and selective than their single-component counterparts in the hydrogenolysis of lignin model compounds and real lignin.
- Zhang, Jiaguang,Teo, Jason,Chen, Xi,Asakura, Hiroyuki,Tanaka, Tsunehiro,Teramura, Kentaro,Yan, Ning
-
p. 1574 - 1583
(2014/05/20)
-
- One-step polyol synthesis of Rh-on-Pd bimetallic nanodendrites and their electrocatalytic properties for ethanol oxidation in alkaline media
-
We report a new, facile and one-step polyol route for the synthesis of Rh-on-Pd bimetallic nanodendrites that are composed of Pd cores with Rh branches. Ethylene glycol is used as a reducing agent while hexadecyltrimethylammonium bromide (CTAB) is used as a structure-directing agent. The as-synthesized nanodendrites are characterized by transmission electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy. It is demonstrated that the morphology and number of Rh branches can be regulated by varying, respectively, the molar ratio of Pd to Rh precursors and the CTAB content. An intriguing finding is that CTAB not only directs the growth of Rh branches but also enables the formation of uniformly-shaped Pd cores. This effective one-step polyol synthesis can be ascribed to the different reduction kinetics between Pd and Rh ions resulting in the formation of Pd cores prior to the growth of the Rh branches. The electrocatalytic properties of the carbon supported Rh-on-Pd bimetallic nanodendrites as the catalyst for ethanol oxidation in alkaline media are investigated. Cyclic voltammetry results show that the Rh-on-Pd/C catalysts display a much higher CO2 selectivity than a Pd/C catalyst. In particular, the ratio of the forward to backward peak current density (j f/jb) of the Rh-on-Pd (3 : 1)/C catalyst is 2.2, which is three times that of the Pd/C catalyst.
- Shen, Shuiyun,Zhao, Tianshou
-
p. 906 - 912
(2013/07/11)
-
- Stabilization of decatellurium molecules in isolated and concatenated clusters
-
Black, shiny crystals of the molecular cluster compounds (Te 10)[M(TeX4)(TeX3)]2 (M/X = Rh/Cl (1), Ir/Br (2)), (Te10)[Ru(TeI4)(TeI2)] 2 (3), (Te10)[M(TeI4)(TeI2)] 2(TeI4)(Te2I2) (M = Rh (4), Ir (5)) as well as the one-dimensional cluster polymer (Te10I 2)[Ir(TeI4)]2(Te4)I2 (6) were synthesized by melting reactions of an electron-rich transition metal M (M = Ru, Rh, Ir) with tellurium and TeX4 (X = Cl, Br, I). X-ray diffraction on single-crystals revealed that the compounds crystallize in the triclinic space group type P1. 4 and 5 show [3+1]-dimensional modulations of their structures. All compounds contain binuclear complexes with central μ-η4:η4-bridging Te10 units and terminal halogenidotellurate(II) groups. Each of the transition metal cations is in a slightly distorted octahedral coordination by six tellurium atoms; the two [MTe6] octahedra share a common edge. With the tellurium atoms acting as electron-pair donors, the 18 electron rule is fulfilled for the electrophilic M atoms. The central tricyclo[5.1.1.13, 5]- decatellurium molecule consists of two ecliptically stacked Te4 rings, which are linked through two tellurium atoms. The symmetric or asymmetric 3c4e bonds along these almost linear bridges are in analogy to polyanionic forms of tellurium, while the tricyclic conformation is stabilized by the strong bonding to the transition-metal cations. Multi-center bonding (3c4e) is also present in the terminal square [Te+IIX4]2- and the T-shaped [Te+IIX3]- groups. The crystal structures of 4 and 5 are organized in layers of (Te10)[M(TeI 4)(TeI2)]2n+ clusters (n ≤ 2) that are quite robust upon oxidation or reduction as shown by molecular calculations. These clusters alternate with incommensurately modulated layers that probably consist of TeI42- anions and a previously unknown Te2I2 molecule. The uncertainty arises primarily from equal scattering powers of I and Te atoms as well as from the known flexibility of the electron count of the Te10 unit. In 6, neutral Te4 rings concatenate (Te10I2)[Ir(TeI 4)]2 clusters into chains, which run parallel to the a axis. Copyright
- Guenther, Anja,Isaeva, Anna,Ruck, Michael
-
p. 254 - 260
(2013/04/10)
-
- Synthetic route to metal nitrides: High-pressure solid-state metathesis reaction
-
We report a general synthetic route to well-crystallized metal nitrides through a high-pressure solid-state metathesis reaction (HPSSM) between boron nitride (BN) and ternary metal oxide AxMyOz (A = alkaline or alkaline-earth metal and M = main group or transition metal). On the basis of the synthetic metal nitrides (Fe3N, Re3N, VN, GaN, CrN, and WxN) and elemental products (graphite, rhenium, indium, and cobalt metals), the HPSSM reaction has been systematically investigated with regard to its general chemical equation, reaction scheme, and characteristics, and its thermodynamic considerations have been explored by density functional theory (DFT) calculations. Our results indicate that pressure plays an important role in the synthesis, which involves an ion-exchange process between boron and the metal ion, opening a new pathway for material synthesis.
- Lei, Li,Yin, Wenwen,Jiang, Xiaodong,Lin, Sen,He, Duanwei
-
p. 13356 - 13362
(2014/01/06)
-
- A facile one-step synthesis of polymer supported rhodium nanoparticles in organic medium and their catalytic performance in the dehydrogenation of ammonia-borane
-
A new type of supported rhodium nanoparticles were reproducibly prepared from N2H4BH3 reduction of [Rh(μ-Cl)(1,5-cod) ]2 without using any solid support and pre-treatment technique. Their characterization shows the formation of well dispersed rhodium(0) nanoparticles within the framework of a polyaminoborane based polymeric support. These new rhodium(0) nanoparticles were found to be the most active supported catalyst in the catalytic dehydrogenation of ammonia-borane in water at room temperature. The Royal Society of Chemistry 2012.
- Karahan, Senem,Zahmakiran, Mehmet,Oezkar, Saim
-
p. 1180 - 1182
(2012/02/03)
-
- Hexatellurium rings in coordination polymers and molecular clusters: Synthesis and crystal structures of [M(Te6)]X3 (M = Rh, Ir; X = Cl, Br, I) and [Ru2(Te6)](TeBr3) 4(TeBr2)2
-
The reaction of an electron-rich transition metal M (M = Ru, Rh, Ir), tellurium and TeX4 (X = Cl, Br, I) resulted in black crystals of five ternary coordination polymers with the general composition [M III(Te6)]X3 (M = Rh, Ir) and of the molecular cluster compound [RuII2(Te6)](Te IIBr3)4(TeIIBr2) 2. X-ray diffraction on single-crystals revealed that the compounds [M(Te6)]X3 crystallize isostructurally in the trigonal space group type Rβar{3}χ. In their crystal structures linear, positively charged [MIII(Te6)] chains form the motif of a hexagonal rod packing. In the chain, each of the formally uncharged Te 6 molecules with chair conformation acts as a bis-tridentate bridging ligand to two M atoms. The octahedrally coordinated M atoms are spiro atoms in the chain of trans vertices sharing heterocubane fragments. Including the isolated halide ions, which provide charge balance, the entire arrangement resembles a cut-out of the α-polonium structure type.In the monoclinic compound Ru2Te12Br16 (space group P2 1/n), the ruthenium atoms of the hetero-cubane core of the molecular cluster [Ru2(Te6)](TeBr3)4(TeBr 2)2 are saturated by terminal bromidotellurate(II) groups. Again, the Te6 ring is formally uncharged. With the tellurium atoms acting as electron-pair donors the 18 electron rule is fulfilled for the M atoms in all compounds. Copyright
- Guenther, Anja,Ruck, Michael
-
p. 317 - 323
(2012/05/20)
-
- Degradation of polycrystalline rhodium and rhodium nanoparticles
-
The electrochemical stability of polycrystalline rhodium and rhodium nanoparticles is quantitatively investigated in non-complexing sulfate electrolyte under potential cycling conditions. In situ measurements of the active surface area are complemented by
- Karschin, Arndt,Katsounaros, Ioannis,Klemm, Sebastian O.,Meier, Josef C.,Mayrhofer, Karl J.J.
-
p. 355 - 359
(2012/06/30)
-
- Arrangement and dispersion of rh and pt atoms on graphene oxide sheets
-
Hybrid materials of ultimately minimized metal particles, namely, isolated atoms or subnano-sized particles, on thermally exfoliated graphene oxide sheets were produced using cationexchanged highly oxidized graphite as a precursor. Rh atoms on graphene sheets arrange with a regular spacing of 0.50 or 0.45 nm and form square or rectangular grid patterns, whereas isolated Pt atoms disperse on graphene sheets randomly.
- Gotoh, Kazuma,Hashimoto, Hideki,Kawai, Ryo,Nishina, Yuta,Fujii, Eiji,Ohkubo, Takahiro,Itadani, Atsushi,Kuroda, Yasushige,Ishida, Hiroyuki
-
p. 680 - 682
(2012/09/22)
-
- Investigation of thermal properties of double complex salts [M(NH3)5Br][AuBr4]2-nH2O, M 5 Rh, Ir
-
Novel double complex salts [M(NH3)5Br] [AuBr4]2-nH2O, M =Rh, Ir, have been synthesized and examined. The processes of thermal decomposition of the compounds in inert and reductive atmospheres have been studied and intermediate products identified. Simultaneous thermal analysis with parallel mass-spectrometric analysis of evolved gases (STA-EGA) has been employed for identification of main gaseous products of thermolysis in inertatmosphere. It has been revealed that the final products of decompositi on in inert or reductive atmospheres are fine powders of gold and the corresponding platinum metal with sizes of crystallites 4-40 nm. The possibility of preparation of the metastable solid solution Au0.05Ir0.95 on thermolysis of [Ir(NH3)5Br][AuBr4]2-H2O in inert atmosphere has been demonstrated.
- Semitut, E. Yu.,Plyusnin, P. E.,Shubin, Yu. V.,Veniaminov, S. A.,Korenev, S. V.
-
p. 901 - 906
(2012/10/08)
-
- Suppression of the water splitting back reaction on GaN:ZnO photocatalysts loaded with core/shell cocatalysts, investigated using a μ-reactor
-
Using silicon-based μ-reactors, we have studied the photocatalytic water splitting reaction and the catalytic back reaction on the same catalysts. GaN:ZnO without cocatalyst and loaded with Rh, Pt, Cr2O 3/Rh, Cr2O3/Pt, and Rh-Cr mixed oxide has been tested for gas-phase photocatalytic water splitting. The results confirm the high activity observed in liquid-phase experiments with Cr2O 3/Rh and Rh-Cr mixed oxide as cocatalysts. To investigate the reason of this enhanced activity, the back reaction was studied by reacting stoichiometric H2/O2 and monitoring the water molecules produced. The comparison of the two experiments shows that the suppression of the back reaction with the core/shell cocatalysts and the Rh-Cr mixed oxide corresponds to an increase in the net photocatalytic water splitting activity. The fact that the back reaction is not completely suppressed with Cr 2O3/Pt compared to Cr2O3/Rh may be the cause of the higher net activity of the Cr2O3/Rh.
- Dionigi, Fabio,Vesborg, Peter C.K.,Pedersen, Thomas,Hansen, Ole,Dahl, Soren,Xiong, Anke,Maeda, Kazuhiko,Domen, Kazunari,Chorkendorff, Ib
-
-
- Effect of the nature of rhodium catalyst supports on initiation of H 2 production during n-butane oxidative reforming at room temperature
-
Three rhodium catalysts supported on rare earth oxides with redox properties, Rh/CeO2, Rh/Pr6O11, and Rh/Tb 4O7, were tested for their ability to trigger oxidative reforming of n-butane at room temper
- Nagaoka, Katsutoshi,Sato, Katsutoshi,Takita, Yusaku
-
-
- Rhodium in presence of platinum as a facilitator of carbon-carbon bond break: A composition study
-
In this work we investigate the acetaldehyde electrooxidation reaction on PtRh electrodeposits as a function of their composition. Potentiodynamic results show that the balance between CO2 and acetic acid pathways depends on the PtRh compositio
- Le?o, Edgard P.,Giz, M. Janete,Camara, Giuseppe A.,Maia, Gilberto
-
p. 1337 - 1343
(2011/04/26)
-
- The reduction of 15N14NO by CO and by H2 over Rh/SiO2: A test of a mechanistic proposal
-
A literature proposal that the reduction of nitrous oxide by carbon monoxide over rhodium catalysts proceeds by cleavage of the NN bond has been tested through the use of 15N14NO as the reactant. The results disprove the suggestion in that 14N15N is the dominant product at temperatures from 336 °C to 356 °C with nitrous oxide conversions from 26% to >99%. Little, if any, 14N 2 and 15N2 is formed, in contrast with the 25% of each expected for the model. Results for the corresponding reaction of 15N14NO with H2 are even more clear-cut in demonstrating the absence of NN bond cleavage. The activity of the Rh/SiO 2 used here for the N2O/CO system fell within the rather wide of values reported in the literature for other Rh catalysts. However, activity for the reduction of N2O by H2 was approximately five times higher than the only previous result in the literature, that for a Rh/Al2O3 catalyst.
- Cant, Noel W.,Chambers, Dean C.,Liu, Irene O.Y.
-
p. 162 - 166
(2011/05/13)
-
- Effective octadecylamine system for nanocrystal synthesis
-
New chemical reactions and synthetic systems are of key importance for materials fabrication. In this work, we reported a facile and effective octadecylamine (ODA) synthetic system for various nanocrystals including metals, mixed metal oxides, metal/metal
- Wang, Dingsheng,Li, Yadong
-
p. 5196 - 5202
(2011/08/08)
-
- New ammonium surfactant-stabilized rhodium(0) colloidal suspensions: Influence of novel counter-anions on physico-chemical and catalytic properties
-
Novel anionic species, such as hydrogen carbonate (HCO3 -), fluoride (F-), triflate (CF3SO 3-), tetrafluoroborate (BF4-) and chloride (Cl-) were investigated as new partners of water soluble N,N-dimethyl-N-cetyl-N-(2-hydroxyethyl) ammonium salts, used as a protective agent of rhodium colloids. The effect of the surfactant polar head on the micellar behavior, size and morphology of the nanospecies was studied by adapted physico-chemical experiments (surface tension measurements, dynamic light scattering, thermogravimetric and TEM analyses) and discussed in terms of strong or weak stabilization of the growing nanoparticles surface. Finally, the influence of the nanoenvironment generated by the surfactant with various counter-anions was evaluated via the hydrogenation of aromatics.
- Guyonnet Bile, Elodie,Sassine, Rita,Denicourt-Nowicki, Audrey,Launay, Franck,Roucoux, Alain
-
p. 6524 - 6531
(2011/08/06)
-
- Nanosize-induced hydrogen storage and capacity control in a non-hydride-forming element: Rhodium
-
We report the first example of nanosize-induced hydrogen storage in a metal that does not absorb hydrogen in its bulk form. Rhodium particles with diameters of 10 nm were found to exhibit hydrogen-storage capability, while bulk Rh does not absorb hydroge
- Kobayashi, Hirokazu,Morita, Hitoshi,Yamauchi, Miho,Ikeda, Ryuichi,Kitagawa, Hiroshi,Kubota, Yoshiki,Kato, Kenichi,Takata, Masaki
-
p. 11034 - 11037
(2011/09/14)
-
- Selectivity of chemisorbed oxygen in C-H bond activation and CO oxidation and kinetic consequences for CH4-O2 catalysis on Pt and Rh clusters
-
Rate measurements, density functional theory (DFT) within the framework of transition state theory, and ensemble-averaging methods are used to probe oxygen selectivities, defined as the reaction probability ratios for O reactions with CO and CH
- Chin, Ya-Huei,Buda, Corneliu,Neurock, Matthew,Iglesia, Enrique
-
-
- Solid-phase room-temperature decomposition of a complex salt trans-[Rh(γ-Pic)4Cl2]MnO4
-
Permanganate salt of the complex cation trans-[Rh(γ-Pic) 4Cl2]+ (γ-Pic = γ-picoline) was synthesized. The unusual decomposition reaction of the salt was studied at room temperature. This process has been found to conserve the γ-picoline ligands in cation untouched. A number of transformations in anionic part of salt have been observed. Metallic products of the salt thermal decomposition have been studied.
- Venediktov, Anatoliy B.,Vasilchenko, Danila B.,Yushina, Irina V.,Nedoseykina, Tatyana I.,Filatov, Evgeniy Yu.,Korenev, Sergey V.
-
p. 1201 - 1206
(2011/05/14)
-
- Profiling the tuneable R-SMS-Phos structure in the rhodium(i)-catalyzed hydrogenation of olefins: The last stand?
-
A diversified family of enantiopure P-stereogenic "R-SMS-Phos" {R-SMS-Phos = 1,2-bis[(o-RO-phenyl)(phenyl)phosphino]ethane} ligands wherein R = branched or heteroatom-substituted alkyl, aralkyl, silyl, acyl, sulfonyl, etc. was screened for the Rh(i)-catalyzed hydrogenation of a representative set of olefinic substrates. This systematic and detailed investigation revealed a marked beneficial impact on enantioselectivity and catalyst activity in comparison to Knowles' ultimate DiPAMP {DiPAMP = 1,2-bis[(o-anisyl)(phenyl) phosphino]ethane} design. Mutant ligands with highly enhanced properties possessing particular features wherein the DiPAMP structure is found embedded were identified. The Royal Society of Chemistry 2011.
- Stephan, Michel,?terk, Damjan,Zupan?i?, Borut,Mohar, Barbara
-
p. 5266 - 5271
(2011/09/20)
-
- Synthesis of nanosize Co-Rh systems and study of their properties
-
Precursor compounds [Co(NH3)6][Rh(NO 2)6] and [Co(NH3)6][Co(NO 2)6], solid solutions [Co(NH3)6] [Rh(NO2)6]1-x [Co(NO2)6] x, and solid solutions Na3[Rh1-x Co x (NO2)6] were synthesized and studied by IRspectroscopy and elemental, X-ray phase, X-ray diffraction, and thermog ravimetric analyses. X-ray phase analysis was employed to examine products of thermal decomposition of precursors in the atmospheres of hydrogenand helium. Catalysts with a Co-Rh active system, supported by ZrO 2, were prepared and tested in the reaction of steam conversion ofethanol.
- Gubanov, A. I.,Churakova, E. M.,Badmaev, S. D.,Sytnikov, P. V.,Filatov, E. Yu.,et al.
-
p. 1677 - 1683
(2012/03/09)
-
- Organometallic control at the nanoscale: A new, one-pot method to decorate a magnetic nanoparticle surface with noble metal atoms
-
A novel cascade of reactions is designed to control in situ the deposition of noble metal islands (e.g. Rh) on top of nanoparticles of a 3d metal (e.g. Fe, Co). The Royal Society of Chemistry.
- Atamena, Nabil,Ciuculescu, Diana,Alcaraz, Gilles,Smekhova, Alevtina,Wilhelm, Fabrice,Rogalev, Andrei,Chaudret, Bruno,Lecante, Pierre,Benfield, Robert E.,Amiens, Catherine
-
p. 2453 - 2455
(2010/06/21)
-
- Relationship between the structural properties of supported bimetallic Pt-Rh catalysts and their performances for methylcyclopentane ring opening
-
Bimetallic Pt-Rh catalysts supported on alumina and silica were synthesized either by the refilling method or by coimpregnation. They were characterized by transmission electron microscopy (TEM), H2 chemisorption, temperature-programmed reduction (TPR), Fourier transform infrared (FTIR) of adsorbed CO and the test reaction of cyclohexane dehydrogenation. Varying the preparation procedure and the nature of the support leads to the formation of bimetallic Pt-Rh particles of different size in the range 1.2-2.7 nm. A Pt surface enrichment and the presence of a Pt-Rh alloy were detected by FTIR of adsorbed CO on the largest particles. The catalytic performances of the Pt-Rh systems were evaluated in methylcyclopentane (MCP) ring opening (RO) under pressure (28.5 bar). All the bimetallic catalysts present an activity much higher than that of the Pt monometallic sample, close to that of the Rh one. At 300 °C, the turnover frequencies are the followings: 115 h-1 for Pt, 4094 h-1 for Rh, between 2264 and 5563 h-1 for the Pt-Rh catalysts whatever the preparation procedure and the nature of the support. On Pt-Rh samples presenting particles with large enough size (>1.7 nm), the RO selectivity at iso-conversion (>50%) is higher than those of monometallic Pt/Al2O3 and Rh/Al2O3 systems, reaching the performances of a monometallic iridium-based sample considered as the most selective catalyst in these conditions. Finally, the refilling method allows obtaining supported Pt-Rh catalysts with the structural properties required to obtain both high activity and RO selectivity during methylcyclopentane hydrogenolysis.
- Samoila,Boutzeloit,Especel,Epron,Marecot
-
p. 237 - 248
(2011/02/27)
-
- Tunable optical features from self-organized rhodium nanostructures
-
Manipulating the surface to tune plasmonic emission is an exciting fundamental challenge and here we report on the development of unique morphology-dependant optical features of Rh nanostructures prepared by an equilibrium procedure. The emergence of surf
- Sathe, Bhaskar R.,Balan, Beena K.,Pillai, Vijayamohanan K.
-
-
- Tunable aqueous phase synthesis and shape-dependent electrochemical properties of rhodium nanostructures
-
Rhodium nanostructures with highly selective morphologies such as cubes, horned particles, dendrites, and network-shaped wires have been achieved through the synergetic effect of sodium lauryl sulfate (SLS) and halogen anions (F -, Cl-, Br-, I-) in a green solvent, water. The effects of SLS and halogen anions were systematically investigated. The electrocatalytic performances of Rh nanostructures toward ethanol oxidation were tested. The results have shown that the rhodium nanostructures displayed shape-dependent properties, and the nanodendrites possessed the maximum catalytic activity.
- Yuan, Qiang,Zhou, Zhiyou,Zhuang, Jing,Wang, Xun
-
p. 5515 - 5521
(2010/08/06)
-
- Perovskite-type oxide catalysts for low temperature, anaerobic catalytic partial oxidation of methane to syngas
-
The cyclic reaction between CH4 and O2 over perovskite-type La0.8Sr0.2Fe0.8Co 0.2O3-δ, La0.75Sr 0.25Fe0.6Co0.15Al0.25O 3-δ and La0.8Sr0.2Fe 0.8Co0.2O3-δ/γ-AlO(OH), impregnated with 0.5 wt% Rh or Pt, was studied at 873 K. Synchrotron X-ray and neutron diffraction patterns of La0.75Sr0.25Fe 0.6Co0.15Al0.25O3- δ proved a rhombohedral structure with Al distributed over the octahedral B-site. The oxygen non-stoichiometry (δ) was determined by thermogravimetric analysis at 958 K for pO2 > 10-22 atm. High selectivity to the partial oxidation products CO and H2 was observed when 3 - δ was lower than 2.76 and 2.78 for the mentioned oxides, with and without Al, respectively. The role of Rh relates solely to the activation of CH4. A stable high selectivity throughout the pulse sequence was achieved when utilizing partially reduced materials. In situ synchrotron XRD proved that the oxides retained the perovskite structure during the reduction/oxidation cycle, and no phase decomposition occurred. The strong correlation between results from catalytic transient tests and thermogravimetric analysis suggests that the CO selectivity is ruled by the redox potential of the reducible oxide.
- Mudu, Federica,Arstad, Bjornar,Bakken, Egil,Fjellvg, Helmer,Olsbye, Unni
-
-
- Facile synthesis of five-fold twinned, starfish-like rhodium nanocrystals by eliminating oxidative etching with a chloride-free precursor
-
Five-fold twinned, starfish-like Rh nanocrystals consisting of five arms (see TEM) have been synthesized in high yields with the use of [{(CF 3COO)2Rh}2] as a precursor to completely eliminate oxidative etching from this system. The as-prepared Rh nanocrystals were shown with great performance as a substrate for SERS. (Figure Presented).
- Zhang, Hui,Xia, Xiaohu,Li, Weiyang,Zeng, Lie,Dai, Yunqian,Yang, Deren,Xia, Younan
-
p. 5296 - 5300
(2010/10/01)
-
- Optimization of Pt-Ir on carbon fiber paper for the electro-oxidation of ammonia in alkaline media
-
Plating bath concentrations of Pt(IV) and Ir(III) have been optimized as well as the total catalytic loading of bimetallic Pt-Ir alloy for the electro-oxidation of ammonia in alkaline media at standard conditions. This was accomplished using cyclic voltam
- Boggs, Bryan K.,Botte, Gerardine G.
-
p. 5287 - 5293
(2011/01/06)
-
- Complex salts trans-[Rh(β-Pic)4Cl2]X (X = Cl-, ReO4-, and ClO4-): Synthesis, crystal structures, and thermal properties
-
Three novel complex salts containing the cation trans-[Rh(β-Pic) 4Cl2]+ with the anions Cl- (I), ReO4- (II), and ClO4- (III) were obtained and characterized by elemental analysis, X-ray diffraction, NMR spectroscopy, and IR spectroscopy. The complex trans-[Rh(β-Pic) 4Cl2]ReO4 crystallizes from DMF as a solvate in which solvent molecules fill the channels formed by the cations and anions. The thermal properties of complexes I, II, and II · DMF were examined by DTA. Final and some intermediate products of the thermolysis were isolated and characterized by physicochemical methods. Pleiades Publishing, Ltd., 2010.
- Vasil'chenko,Filatov,Baidina,Plyusnin,Korenev
-
p. 347 - 352
(2010/09/17)
-
- Synthesis of oxygen- and sulfur-bridged dirhodium complexes and their use as catalysts in the chemoselective hydrogenation of alkenes
-
Oxygen-bridged and sulfur-bridged rhodium homobimetallic complexes were synthesized as air-stable crystals by using 2,6-bis(phosphanylmethyl)phenolate and -thiophenolate as the ligands, respectively. The oxygen-bridged dirhodium complex has a symmetrical structure where the carbon atom at the ipso position, oxygen, and two rhodium atoms are located in the same plane. It is thermally stable compared to the sulfur-bridged dirhodium complex and shows catalytic activity for hydrogenation of alkenes with high chemoselectivity.
- Zhu, Chuan,Yukimura, Noriaki,Yamane, Motoki
-
p. 2098 - 2103
(2010/06/19)
-
- PROCESS FOR HYDROGENATION OF AN AROMATIC FEEDSTOCK THAT AS CATALYST USES A SUSPENSION OF METAL NANOPARTICLES CONTAINING A NITROGEN-CONTAINING LIGAND IN AN IONIC LIQUID
-
This invention describes a process for hydrogenation of an aromatic feedstock that as a catalytic composition uses a suspension of metal nanoparticles of a mean size of between 1 and 20 nanometers in at least one non-aqueous ionic liquid, whereby said suspension also contains at least one nitrogen-containing ligand, in which said metal nanoparticles comprise a transition metal in the zero-valence state, whereby the transition metal is selected from the groups 8, 9, 10 and 11 of the periodic table and in which said nitrogen-containing ligand comprises 1 to n nitrogen atoms, whereby n is an integer of between 1 and 20.
- -
-
Page/Page column 6-7
(2010/09/17)
-
- Evidence for heterogeneous Sonogashira coupling of phenylacetylene and iodobenzene catalyzed by well defined rhodium nanoparticles
-
Sonogashira coupling of phenylacetylene with iodobenzene has been studied in the presence of metallic Rh nanoparticle catalysts and found to occur via a surface-mediated heterogeneous route. Homogeneous catalytic processes due to Rh species that may leach into solution were barely detectable within the sensitivity of our experiments. Moreover, larger (8 nm) nanoparticles were found to be much better catalysts than very small ones (2 nm), which is consistent with the hypothesis that steric limitations adversely affect the efficiency of the latter.
- Kanuru, Vijay K.,Humphrey, Simon M.,Kyffin, John M. W.,Jefferson, David A.,Burton, Jonathan W.,Armbruester, Marc,Lambert, Richard M.
-
p. 7602 - 7605
(2010/02/16)
-
- Room-temperature hydrogen generation from hydrous hydrazine for chemical hydrogen storage
-
(Graph Presented) Rhodium nanoparticles (NPs) effectively catalyze the decomposition of hydrous hydrazine to produce hydrogen under ambient reaction conditions. Rh(0) NPs with a particle size of ~5 nm prepared in the presence of hexadecyltrimethyl ammoniu
- Sanjay, Kumar Singh,Zhang, Xin-Bo,Xu, Qiang
-
p. 9894 - 9895
(2009/12/06)
-
- Catalytic performance and characterization of Rh-CeO2/MgO catalysts for the catalytic partial oxidation of methane at short contact time
-
The addition of an optimum amount of CeO2 (Ce/Rh = 4) to 1.0 wt% Rh/MgO promoted the catalytic partial oxidation (CPO) of methane with N2 dilution. At the same time, it can suppress the temperature increase at the catalyst bed inlet
- Tanaka, Hisanori,Kaino, Rie,Okumura, Kazu,Kizuka, Tokushi,Tomishige, Keiichi
-
-
- Preparation of rhodium nanoparticles in carbon dioxide induced ionic liquids and their application to selective hydrogenation
-
(Figure Presented) In the trap: Catalytically active nanoparticles can be generated and stabilized in solid ionic matrices with the aid of supercritical CO2. The method allows the use of simple ammonium salts that would not be classified as ion
- Cimpeanu, Valentin,Ko?evar, Marijan,Parvulescu, Vasile I.,Leitner, Walter
-
p. 1085 - 1088
(2009/06/19)
-
- Synthesis of Co, Rh and Ir nanoparticles from metal carbonyls in ionic liquids and their use as biphasic liquid-liquid hydrogenation nanocatalysts for cyclohexene
-
Stable cobalt, rhodium and iridium nanoparticles are obtained reproducibly by thermal decomposition under argon from Co2(CO)8, Rh6(CO)16 and Ir4(CO)12 dissolved in the ionic liquids BMimsu
- Redel, Engelbert,Kr?mer, Jér?me,Thomann, Ralf,Janiak, Christoph
-
p. 1069 - 1075
(2009/07/18)
-
- Aqueous-phase biphasic dehydroaromatization of bio-derived limonene into p-cymene by soluble Pd nanocluster catalysts
-
A biphasic approach to the dehydroaromatization of bioderived limonene into water-insoluble p-cymene using soluble Pd nanoparticle catalysts in an aqueous phase (≥150 °C, 2 bar H2) was successfully achieved with a conversion of 93% and a selectivity of 82%. The Pd nanoparticles, operating under forcing conditions (180 °C, 2 bar H2), can be recycled at least four times without noticeable degradation. The effects of temperature, pressure, reaction time, pH, catalyst concentration, metal type, the type and amount of polymer stabilizer, and the preparation method were systematically investigated to optimize the process and provide insight into the mechanisms involved.
- Zhao, Chen,Gan, Weijia,Fan, Xiaobing,Cai, Zhipeng,Dyson, Paul J.,Kou, Yuan
-
p. 244 - 250
(2008/09/18)
-
- Iodide ions control galvanic replacement growth of uniform rhodium nanotubes at room temperature
-
Hollow rhodium nanotubes with uniform and perfect structures have been successfully synthesized through the replacement reaction between Ag nanowires and RhCl3 in saturated NaI solutions at room temperature, and the main effect of iodide ions i
- Bi, Yingpu,Lu, Gongxuan
-
p. 6402 - 6404
(2009/04/13)
-
- Rh-Pt bimetallic catalysts: Synthesis, characterization, and catalysis of core-shell, alloy, and monometallic nanoparticles
-
Rh?Pt core-shell, RhPt (1:1) alloy, and Rh + Pt monometallic nanoparticles (NPs) were prepared using standard polyol reduction chemistry in ethylene glycol (EG) with standard inorganic salts and polyvinylpyrrolidine (PVP 550oo) stabilizers. PVP-free colloids were also prepared but less stable than the PVP-protected NPs. Rh?Pt core-shell particles were prepared from 2.7, 3.3, and 3.9 nm Rh cores with varying shell thicknesses (~1 and ~2 ML). The particles were characterized by a combination of TEM, single-particle EDS, EDS line scans, XRD analysis, Debye Function simulations, FT-IR, and micro-Raman CO-probe experiments. The three different architectures were evaluated for preferential oxidation of CO in hydrogen (PROX) using 1.0 wt % Pt loadings in Al203 supports. For hydrogen feeds with 0.2% CO and 0.5% 02 the Rh?Pt NP catalyst has the best activity with complete CO oxidation at 70 °C and very high PROX selectivity at 40 °C with 50% CO conversion.
- Alayoglu, Selim,Eichhorn, Bryan
-
p. 17479 - 17486
(2009/06/08)
-
- CoFeRh alloys. Part 1. Electrodeposition of Rh and nonmagnetic CoFeRh alloy
-
The electrochemical behavior of Rh(III) species in CoFe solution containing RhCl3, NH4Cl, H3BO3, CoSO4, FeSO4, saccharin, and NaLS (Na lauryl sulfate) has been investigated. The electrochemistry of Rh(III) species is influenced by each of the compounds present in CoFe plating solution, but especially by addition of saccharin and H3BO3 to the RhCl3-NH4Cl solution. The nucleation and growth of Rh on GC (glassy carbon), Ru, and Cu electrodes from NH4Cl solution was studied using the potentiostatic current-transient methods. The results support a predominantly progressive nucleation of Rh on all three-electrode surfaces. The nucleation kinetic parameters ANo (steady state nucleation rate) and Ns (saturation nuclear number density) were found to vary with potential and are electrode-dependent in order: GC > Ru~Cu. The electrodeposited Rh films obtained from NH4Cl solution and nonmagnetic CoFeRh film obtained from CoFe solution were characterized in terms of the following properties: morphology, surface roughness, crystal structure and chemical composition. The origin of light elements found in Rh and CoFeRh films (O, Cl, S, C, N) was discussed.
- Tabakovic, Ibro,Qiu, Jiao-Ming,Riemer, Steve,Sun, Ming,Vas'ko, Vlad,Kief, Mark
-
p. 2483 - 2493
(2008/10/09)
-
- Template-assisted synthesis of shape-controlled Rh2P nanocrystals
-
When reacted with trioctylphosphine at ~360°C, rhodium nanocrystals convert to rhodium phosphide (Rh2P) nanocrystals. Careful control over synthetic variables, such as temperature, stabilizing ligands, and cosolvents, can result in Rh2P nanocrystals with shapes that reflect the Rh nanocrystal templates. Accordingly, Rh nanocrystals with multipod, cube- and triangle-derived shapes convert to Rh2P nanocrystals that maintain the shape of their Rh precursors. Both dense and hollow Rh2P nanocrystals can be generated using a single unified chemical conversion strategy. These empirical guidelines for generating a morphologically diverse library of Rh2P nanocrystals provide important insights into shape conservation using nanocrystal templates and will likely be portable to other multielement systems for which rigorous shape-controlled synthesis remains challenging.
- Henkes, Amanda E.,Schaak, Raymond E.
-
p. 671 - 677
(2008/10/09)
-
- Process for the preparation of acetic acid and/or methyl acetate
-
Process for the production of acetic acid and/or methyl acetate by contacting methanol and/or a reactive derivative thereof with a decomposition catalyst to produce a mixture of carbon monoxide and hydrogen and subsequently catalytically converting the carbon monoxide and hydrogen to acetic acid and/or methyl acetate.
- -
-
-
- Chiral dendrimer encapsulated Pd and Rh nanoparticles
-
The synthesis of a series of chiral PAMAM dendrimers and the formation of chiral dendrimer encapsulated metal nanoparticles are described. The Royal Society of Chemistry.
- Pittelkow, Michael,Brock-Nannestad, Theis,Moth-Poulsen, Kasper,Christensen, Jorn B.
-
p. 2358 - 2360
(2009/02/03)
-
- Enhanced field emission from hexagonal rhodium nanostructures
-
Shape selective synthesis of nanostructured Rh hexagons has been demonstrated with the help of a modified chemical vapor deposition using rhodium acetate. An ultralow threshold field of 0.72 Vμm is observed to generate a field emission current density of 4 × 10-3 μA/cm 2. The high enhancement factor (9325) indicates that the origin of electron emission is from nanostructured features. The smaller size of emitting area, excellent current density, and stability over a period of more than 3 h are promising characteristics for the development of electron sources.
- Sathe, Bhaskar R.,Kakade, Bhalchandra A.,Mulla, Imtiaz S.,Pillai, Vijayamohanan K.,Late, Dattatray J.,More, Mahendra A.,Joag, Dilip S.
-
-