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Electron-induced deposition using Fe(CO) 4MA and Fe(CO) 5 - effect of MA ligand and process conditions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:500-516. [PMID: 38745584 PMCID: PMC11092064 DOI: 10.3762/bjnano.15.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024]
Abstract
The electron-induced decomposition of Fe(CO)4MA (MA = methyl acrylate), which is a potential new precursor for focused electron beam-induced deposition (FEBID), was investigated by surface science experiments under UHV conditions. Auger electron spectroscopy was used to monitor deposit formation. The comparison between Fe(CO)4MA and Fe(CO)5 revealed the effect of the modified ligand architecture on the deposit formation in electron irradiation experiments that mimic FEBID and cryo-FEBID processes. Electron-stimulated desorption and post-irradiation thermal desorption spectrometry were used to obtain insight into the fate of the ligands upon electron irradiation. As a key finding, the deposits obtained from Fe(CO)4MA and Fe(CO)5 were surprisingly similar, and the relative amount of carbon in deposits prepared from Fe(CO)4MA was considerably less than the amount of carbon in the MA ligand. This demonstrates that electron irradiation efficiently cleaves the neutral MA ligand from the precursor. In addition to deposit formation by electron irradiation, the thermal decomposition of Fe(CO)4MA and Fe(CO)5 on an Fe seed layer prepared by EBID was compared. While Fe(CO)5 sustains autocatalytic growth of the deposit, the MA ligand hinders the thermal decomposition in the case of Fe(CO)4MA. The heteroleptic precursor Fe(CO)4MA, thus, offers the possibility to suppress contributions of thermal reactions, which can compromise control over the deposit shape and size in FEBID processes.
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Aerosol-Assisted Chemical Vapor Deposition of 2H-WS 2 From Single-Source Tungsten Dithiolene Precursors. JOURNAL OF MATERIALS CHEMISTRY. C 2024; 12:3526-3534. [PMID: 38756620 PMCID: PMC11095848 DOI: 10.1039/d3tc03755j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
The tungsten carbonyl dimethyldithiolene (dmdt) complexes W(CO)4(dmdt), W(CO)2(dmdt)2, and W(dmdt)3 were evaluated as potential single-source precursors for the chemical vapor deposition of WS2. The results of TGA-MS, DIP-MS, and pyrolysis with NMR analysis were consistent with a thermal decomposition pathway in which loss of 2-butyne through a retro[3+2]cycloaddition of the dithiolene ligand generated terminal sulfido ligands. Aerosol-assisted chemical vapor deposition onto silicon substrates was performed using all three complexes, yielding 2H-WS2 thin films as characterized by Raman spectroscopy and GI-XRD. Film morphology and elemental composition of the films were determined using SEM, EDS, and XPS. Four-point probe measurements afforded a film resistivity of 8.37 Ωcm for a sample deposited from W(dmdt)3 in toluene at 600 °C.
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Aerosol-Assisted Chemical Vapor Deposition of MoS 2 with a Thiourea Sulfur Source: Single-Source Precursors vs Coreactant Mixtures. ACS APPLIED MATERIALS & INTERFACES 2023; 15:37764-37774. [PMID: 37493647 DOI: 10.1021/acsami.3c04086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Aerosol-assisted chemical vapor deposition of MoS2 from solutions containing the single-source precursors cis-Mo(CO)4(TMTU)2 and Mo(CO)5(TMTU) in toluene was compared to depositions from the coreactant solution containing Mo(CO)6 and uncoordinated TMTU in toluene. The results were used to assess the significance of ligand precoordination on the properties of the deposited films. Raman spectra and GI-XRD patterns of the films show that the single-source precursors produced more intense and sharper signals for 2H-MoS2 as compared to the coreactant system of Mo(CO)6 and TMTU, which is indicative of improved crystallinity. SEM and XPS were also used to assess morphology and film composition. Thermolysis of cis-Mo(CO)4(TMTU)2 and analysis of the pyrolysis products by GC-MS and 1H NMR suggested a decomposition mechanism of the TMTU ligand where a terminal sulfido is generated on the molybdenum center with loss of a heteroatom stabilized carbene.
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Molybdenum(III) Amidinate: Synthesis, Characterization, and Vapor Phase Growth of Mo-Based Materials. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37450887 DOI: 10.1021/acsami.3c04074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
The synthesis, characterization, and thermogravimetric analysis of tris(N,N'-di-isopropylacetamidinate)molybdenum(III), Mo(iPr-AMD)3, are reported. Mo(iPr-AMD)3 is a rare example of a homoleptic mononuclear complex of molybdenum(III) and fills a longstanding gap in the literature of transition metal(III) trisamidinate complexes. Thermogravimetric analysis (TGA) reveals excellent volatilization at elevated temperatures, pointing to potential applications as a vapor phase precursor for higher temperature atomic layer deposition (ALD), or chemical vapor deposition (CVD) growth of Mo-based materials. The measured TGA temperature window was 200-314 °C for samples in the 3-20 mg range. To validate the utility of Mo(iPr-AMD)3, we demonstrate aerosol-assisted CVD growth of MoO3 from benzonitrile solutions of Mo(iPr-AMD)3 at 500 °C using compressed air as the carrier gas. The resulting films are characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy. We further demonstrate the potential for ALD growth at 200 °C with a Mo(iPr-AMD)3/Ar purge/300 W O2 plasma/Ar purge sequence, yielding ultrathin films which retain a nitride/oxynitride component. Our results highlight the broad scope utility and potential of Mo(iPr-AMD)3 as a stable, high-temperature precursor for both CVD and ALD processes.
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In Support of Early-Career Researchers. J Org Chem 2023; 88:1923-1927. [PMID: 36727963 DOI: 10.1021/acs.joc.3c00130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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In Support of Early-Career Researchers. Inorg Chem 2023; 62:2489-2493. [PMID: 36727951 DOI: 10.1021/acs.inorgchem.3c00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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In Support of Early-Career Researchers. Org Lett 2023; 25:715-719. [PMID: 36727953 DOI: 10.1021/acs.orglett.3c00187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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8
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In Support of Early-Career Researchers. Org Process Res Dev 2023. [DOI: 10.1021/acs.oprd.3c00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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In Support of Early-Career Researchers. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Molybdenum(IV) dithiocarboxylates as single-source precursors for AACVD of MoS 2 thin films. Dalton Trans 2022; 51:12540-12548. [PMID: 35913376 PMCID: PMC9426634 DOI: 10.1039/d2dt01852g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tetrakis(dithiocarboxylato)molybdenum(IV) complexes of the type Mo(S2CR)4 (R = Me, Et, iPr, Ph) were synthesized, characterized, and prescreened as precursors for aerosol assisted chemical vapor deposition (AACVD) of MoS2 thin films. The thermal behavior of the complexes as determined by TGA and GC-MS was appropriate for AACVD, although the complexes were not sufficiently volatile for conventional CVD bubbler systems. Thin films of MoS2 were grown by AACVD at 500 °C from solutions of Mo(S2CMe)4 in toluene. The films were characterized by GIXRD diffraction patterns which correspond to a 2H-MoS2 structure in the deposited film. Mo-S bonding in 2H-MoS2 was further confirmed by XPS and EDS. The film morphology, vertically oriented structure, and thickness (2.54 μm) were evaluated by FE-SEM. The Raman E12g and A1g vibrational modes of crystalline 2H-MoS2 were observed. These results demonstrate the use of dithiocarboxylato ligands for the chemical vapor deposition of metal sulfides.
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Photochemistry of (η 4-diene)Ru(CO) 3 Complexes as Precursor Candidates for Photoassisted Chemical Vapor Deposition. Organometallics 2022. [DOI: 10.1021/acs.organomet.1c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Charged Particle-Induced Surface Reactions of Organometallic Complexes as a Guide to Precursor Design for Electron- and Ion-Induced Deposition of Nanostructures. ACS APPLIED MATERIALS & INTERFACES 2021; 13:48333-48348. [PMID: 34633789 DOI: 10.1021/acsami.1c12327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Focused electron beam-induced deposition (FEBID) and focused ion beam-induced deposition (FIBID) are direct-write fabrication techniques that use focused beams of charged particles (electrons or ions) to create 3D metal-containing nanostructures by decomposing organometallic precursors onto substrates in a low-pressure environment. For many applications, it is important to minimize contamination of these nanostructures by impurities from incomplete ligand dissociation and desorption. This spotlight on applications describes the use of ultra high vacuum surface science studies to obtain mechanistic information on electron- and ion-induced processes in organometallic precursor candidates. The results are used for the mechanism-based design of custom precursors for FEBID and FIBID.
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Electron beam-induced deposition of platinum from Pt(CO) 2Cl 2 and Pt(CO) 2Br 2. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1789-1800. [PMID: 33299738 PMCID: PMC7705861 DOI: 10.3762/bjnano.11.161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Two platinum precursors, Pt(CO)2Cl2 and Pt(CO)2Br2, were designed for focused electron beam-induced deposition (FEBID) with the aim of producing platinum deposits of higher purity than those deposited from commercially available precursors. In this work, we present the first deposition experiments in a scanning electron microscope (SEM), wherein series of pillars were successfully grown from both precursors. The growth of the pillars was studied as a function of the electron dose and compared to deposits grown from the commercially available precursor MeCpPtMe3. The composition of the deposits was determined using energy-dispersive X-ray spectroscopy (EDX) and compared to the composition of deposits from MeCpPtMe3, as well as deposits made in an ultrahigh-vacuum (UHV) environment. A slight increase in metal content and a higher growth rate are achieved in the SEM for deposits from Pt(CO)2Cl2 compared to MeCpPtMe3. However, deposits made from Pt(CO)2Br2 show slightly less metal content and a lower growth rate compared to MeCpPtMe3. With both Pt(CO)2Cl2 and Pt(CO)2Br2, a marked difference in composition was found between deposits made in the SEM and deposits made in UHV. In addition to Pt, the UHV deposits contained halogen species and little or no carbon, while the SEM deposits contained only small amounts of halogen species but high carbon content. Results from this study highlight the effect that deposition conditions can have on the composition of deposits created by FEBID.
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Photochemistry of 1,5-Cyclooctadiene Platinum Complexes for Photoassisted Chemical Vapor Deposition. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Efficient NH 3-based process to remove chlorine from electron beam deposited ruthenium produced from (η 3-C 3H 5)Ru(CO) 3Cl. Sci Rep 2020; 10:10901. [PMID: 32616780 PMCID: PMC7331610 DOI: 10.1038/s41598-020-67803-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 06/12/2020] [Indexed: 11/09/2022] Open
Abstract
The fabrication of Ru nanostructures by focused electron beam induced deposition (FEBID) requires suitable precursor molecules and processes to obtain the pure metal. So far this is problematic because established organometallic Ru precursors contain large organic ligands, such as cyclopentadienyl anions, that tend to become embedded in the deposit during the FEBID process. Recently, (η3-C3H5)Ru(CO)3X (X = Cl, Br) has been proposed as an alternative precursor because CO can easily desorb under electron exposure. However, allyl and Cl ligands remain behind after electron irradiation and the removal of the halide requires extensive electron exposures. Auger electron spectroscopy is applied to demonstrate a postdeposition purification process in which NH3 is used as a reactant that enhances the removal of Cl from deposits formed by electron irradiation of thin condensed layers of (η3-C3H5)Ru(CO)3Cl. The loss of CO from the precursor during electron-induced decomposition enables a reaction between NH3 and the Cl ligands that produces HCl. The combined use of electron-stimulated desorption experiments and thermal desorption spectrometry further reveals that thermal reactions contribute to the loss of CO in the FEBID process but remove only minor amounts of the allyl and Cl ligands.
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Checking in with Women Materials Scientists During a Global Pandemic: May 2020. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2020; 32:4859-4862. [PMID: 37556256 PMCID: PMC7294896 DOI: 10.1021/acs.chemmater.0c02211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
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Synthesis and Evaluation of Molybdenum Imido-Thiolato Complexes for the Aerosol-Assisted Chemical Vapor Deposition of Nitrogen-Doped Molybdenum Disulfide. Organometallics 2020. [DOI: 10.1021/acs.organomet.9b00705] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Identifying and Rationalizing the Differing Surface Reactions of Low-Energy Electrons and Ions with an Organometallic Precursor. J Phys Chem Lett 2020; 11:2006-2013. [PMID: 32058722 DOI: 10.1021/acs.jpclett.0c00061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Surface reactions of electrons and ions with physisorbed organometallic precursors are fundamental processes in focused electron and ion beam-induced deposition (FEBID and FIBID, respectively) of metal-containing nanostructures. Markedly different surface reactions occur upon exposure of nanometer-scale films of (η5-Cp)Fe(CO)2Re(CO)5 to low-energy electrons (500 eV) compared to argon ions (860 eV). Electron-induced surface reactions are initiated by electronic excitation and fragmentation of (η5-Cp)Fe(CO)2Re(CO)5, causing half of the CO ligands to desorb. Residual CO ligands decompose under further electron irradiation. In contrast, Ar+-induced surface reactions proceed by an ion-molecule momentum/energy transfer process, causing the desorption of all CO ligands without significant ion-induced precursor desorption. This initial decomposition step is followed by ion-induced sputtering of the deposited atoms. The fundamental insights derived from this study can be used not only to rationalize the composition of deposits made by FEBID and FIBID but also to inform the choice of a charged particle deposition strategy and the design of new precursors for these emerging nanofabrication tools.
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Dissociation of the FEBID precursor cis-Pt(CO) 2Cl 2 driven by low-energy electrons. Phys Chem Chem Phys 2020; 22:6100-6108. [PMID: 32025665 DOI: 10.1039/c9cp06633k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we present experimental and theoretical results on dissociative electron attachment and dissociative ionisation for the potential FEBID precursor cis-Pt(CO)2Cl2. UHV surface studies have shown that high purity platinum deposits can be obtained from cis-Pt(CO)2Cl2. The efficiency and energetics of ligand removal through these processes are discussed and experimental appearance energies are compared to calculated thermochemical thresholds. The present results demonstrate the potential effectiveness of electron-induced reactions in the deposition of this FEBID precursor, and these are discussed in conjunction with surface science studies on this precursor and the design of new FEBID precursors.
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Photochemistry of (η3-allyl)Ru(CO)3X Precursors for Photoassisted Chemical Vapor Deposition. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00628] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Focused Electron Beam-Induced Deposition and Post-Growth Purification Using the Heteroleptic Ru Complex (η 3-C 3H 5)Ru(CO) 3Br. ACS APPLIED MATERIALS & INTERFACES 2019; 11:28164-28171. [PMID: 31310091 DOI: 10.1021/acsami.9b07634] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Focused electron beam-induced deposition using the heteroleptic complex (η3-C3H5)Ru(CO)3Br as a precursor resulted in deposition of material with Ru content of 23 at. %. Transmission electron microscopy images indicated a nanogranular structure of pure Ru nanocrystals, embedded into a matrix containing carbon, oxygen, and bromine. The deposits were purified by annealing in a reactive 98% N2/2% H2 atmosphere at 300 °C, resulting in a reduction of contaminants and an increase of the Ru content to 83 at. %. Although a significant volume loss of 79% was found, the shrinkage was observed mostly for vertical thickness (around 75%). The lateral dimensions decreased much less significantly (around 9%). Deposition results, in conjunction with previous gas-phase and condensed-phase surface studies on the electron-induced reactions of (η3-C3H5)Ru(CO)3Br, provide insights into the behavior of allyl, carbonyl, and bromide ligands under identical electron beam irradiation.
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Growth of WO x from Tungsten(VI) Oxo-Fluoroalkoxide Complexes with Partially Fluorinated β-Diketonate/β-Ketoesterate Ligands: Comparison of Chemical Vapor Deposition to Aerosol-Assisted CVD. ACS APPLIED MATERIALS & INTERFACES 2019; 11:28180-28188. [PMID: 31314491 DOI: 10.1021/acsami.9b08830] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Tungsten(VI) oxo complexes of the type WO(OR)3L [R = C(CH3)2CF3, C(CF3)2CH3, CH(CF3)2, L = hexafluoroacetylacetonate (hfac), ethyl trifluoroacetoacetonate (etfac), acetylacetonate (acac)] bearing partially fluorinated alkoxide and/or chelating ligands were synthesized. Thermal decomposition behavior and mass spectrometry (MS) fragmentation patterns of selected examples were studied. The thermolysis products of WO(OC(CF3)2CH3)3(hfac) were characterized by nuclear magnetic resonance and gas chromatography-MS. Studies of the sublimation behavior of the complexes demonstrated that their volatility depends on the degree of fluorination. Comparative studies of the deposition of tungsten oxide by chemical vapor deposition (CVD) and aerosol-assisted CVD were carried out using WO(OC(CF3)2CH3)3(hfac) as a single-source precursor. WOx materials were successfully deposited by both deposition methods, but the deposits differed in morphology, structure, and crystallinity.
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Design, Synthesis, and Evaluation of CF 3AuCNR Precursors for Focused Electron Beam-Induced Deposition of Gold. ACS APPLIED MATERIALS & INTERFACES 2019; 11:11976-11987. [PMID: 30835431 DOI: 10.1021/acsami.8b18368] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The Au(I) complexes CF3AuCNMe (1a) and CF3AuCN tBu (1b) were investigated as Au(I) precursors for focused electron beam-induced deposition (FEBID) of metallic gold. Both 1a and 1b are sufficiently volatile for sublimation at 125 ± 1 mTorr in the temperature range of roughly 40-50 °C. Electron impact mass spectra of 1a-b show gold-containing ions resulting from fragmenting the CF3 group and the CNR ligand, whereas in negative chemical ionization of 1a-b, the major fragment results from dealkylation of the CNR ligand. Steady-state depositions from 1a in an Auger spectrometer produce deposits with a similar gold content to the commercial precursor Me2Au(acac) (3) deposited under the same conditions, while the gold content from 1b is less. These results enable us to suggest the likely fate of the CF3 and CNR ligands during FEBID.
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Synthesis of β-ketoiminate and β-iminoesterate tungsten (VI) oxo-alkoxide complexes as AACVD precursors for growth of WO thin films. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.10.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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N,N-Disubstituted-N'-acylthioureas as modular ligands for deposition of transition metal sulfides. Dalton Trans 2018; 47:2719-2726. [PMID: 29411810 DOI: 10.1039/c7dt04860b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First row transition metal complexes (Ni, Co, Cu, Zn) with N,N-disubstituted-N'-acylthiourea ligands have been synthesized and characterized. Bis(N,N-diisopropyl-N'-cinnamoylthiourea)nickel was found to have the lowest onset temperature for thermal decomposition. Thin film deposition of Ni, Co, and Zn sulfides by aerosol assisted chemical vapor deposition from their respective N,N-diisopropyl-N'-cinnamoylthiourea complexes at 350 °C has been demonstrated.
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Synthesis and Characterization of Tungsten Nitrido Amido Guanidinato Complexes as Precursors for Chemical Vapor Deposition of WN xC y Thin Films. Eur J Inorg Chem 2018; 2018:46-53. [PMID: 31467483 DOI: 10.1002/ejic.201701225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tungsten nitrido amido guanidinato complexes of the type WN(NR2)[(NR')2C(NR2)]2 (R = Me, Et; R' = i Pr, Cy) were synthesized as precursors for aerosol-assisted chemical vapor deposition (AACVD) of WNxCy thin films. The reaction of tungsten nitrido amido complexes of the type WN(NR2)3 (R = Me, Et) with two equivalents of a carbodiimide R'N=C=NR' (R' = i Pr, Cy) resulted in two insertions of a carbodiimide into W-N(amido) bonds, affording bis(guanidinato) amido nitrido tungsten complexes. These compounds were characterized by 14N NMR, indicating distinctive chemical shifts for each type of N-bound ligand. Crystallographic structure determination of WN(NMe2)[(N i Pr)2C(NMe2)]2 showed the guanidinato ligands to be non-equivalent. The complex WN(NMe2)[(N i Pr)2C(NMe2)]2 was demonstrated to serve as a precursor for AACVD of WNxCy thin films, resulting in featureless, X-ray amorphous thin films for growth temperatures 200 - 400 °C.
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Low energy electron-induced decomposition of (η5-Cp)Fe(CO)2Mn(CO)5, a potential bimetallic precursor for focused electron beam induced deposition of alloy structures. Phys Chem Chem Phys 2018; 20:5644-5656. [DOI: 10.1039/c7cp06705d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Low energy electron-induced decomposition of a potential bimetallic nanofabrication precursor is studied in gas-phase, at surfaces and by quantum chemical calculations.
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Electron induced surface reactions of (η5-C5H5)Fe(CO)2Mn(CO)5, a potential heterobimetallic precursor for focused electron beam induced deposition (FEBID). Phys Chem Chem Phys 2018; 20:7862-7874. [DOI: 10.1039/c7cp07994j] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron-induced surface reactions of (η5-C5H5)Fe(CO)2Mn(CO)5were exploredin situunder ultra-high vacuum conditions using X-ray photoelectron spectroscopy and mass spectrometry.
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Halide Effects on the Sublimation Temperature of X-Au-L Complexes: Implications for Their Use as Precursors in Vapor Phase Deposition Methods. ACS APPLIED MATERIALS & INTERFACES 2017; 9:40998-41005. [PMID: 29096063 DOI: 10.1021/acsami.7b12465] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Trends in volatility with changes in the halide ligand were established for gold(I) complexes of the type X-Au-L [X = Cl, Br, I; L = CNtBu, CNMe, PMe3, P(NMe2)3, P(OCH2CF3)3] by determining the temperatures for the onset of sublimation (Tsub) at a fixed pressure. Within each series of isocyanide complexes, Tsub decreases with increasing atomic radius of the halide, making the iodide complex the most volatile. For the phosphine and phosphoramidate complexes, the chloride and bromide have similar Tsub values with the bromide slightly higher, but the iodide complex is again the most volatile of the three. The trends in volatility can be correlated to variation in Au-Au bond distances and aggregation patterns in the solid state structures. For the P(OCH2CF3)3 complexes, melting occurred before sublimation, but the iodide complex was still more volatile than the bromide. These trends have implications for the use of these complexes in electron beam induced deposition and chemical vapor deposition, for which precursor volatility is important.
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Comparing postdeposition reactions of electrons and radicals with Pt nanostructures created by focused electron beam induced deposition. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2410-2424. [PMID: 29234576 PMCID: PMC5704761 DOI: 10.3762/bjnano.8.240] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/18/2017] [Indexed: 05/31/2023]
Abstract
The ability of electrons and atomic hydrogen (AH) to remove residual chlorine from PtCl2 deposits created from cis-Pt(CO)2Cl2 by focused electron beam induced deposition (FEBID) is evaluated. Auger electron spectroscopy (AES) and energy-dispersive X-ray spectroscopy (EDS) measurements as well as thermodynamics calculations support the idea that electrons can remove chlorine from PtCl2 structures via an electron-stimulated desorption (ESD) process. It was found that the effectiveness of electrons to purify deposits greater than a few nanometers in height is compromised by the limited escape depth of the chloride ions generated in the purification step. In contrast, chlorine atoms can be efficiently and completely removed from PtCl2 deposits using AH, regardless of the thickness of the deposit. Although AH was found to be extremely effective at chemically purifying PtCl2 deposits, its viability as a FEBID purification strategy is compromised by the mobility of transient Pt-H species formed during the purification process. Scanning electron microscopy data show that this results in the formation of porous structures and can even cause the deposit to lose structural integrity. However, this phenomenon suggests that the use of AH may be a useful strategy to create high surface area Pt catalysts and may reverse the effects of sintering. In marked contrast to the effect observed with AH, densification of the structure was observed during the postdeposition purification of PtC x deposits created from MeCpPtMe3 using atomic oxygen (AO), although the limited penetration depth of AO restricts its effectiveness as a purification strategy to relatively small nanostructures.
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Photochemical CVD of Ru on functionalized self-assembled monolayers from organometallic precursors. J Chem Phys 2017; 146:052816. [PMID: 28178809 DOI: 10.1063/1.4971434] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Chemical vapor deposition (CVD) is an attractive technique for the metallization of organic thin films because it is selective and the thickness of the deposited film can easily be controlled. However, thermal CVD processes often require high temperatures which are generally incompatible with organic films. In this paper, we perform proof-of-concept studies of photochemical CVD to metallize organic thin films. In this method, a precursor undergoes photolytic decomposition to generate thermally labile intermediates prior to adsorption on the sample. Three readily available Ru precursors, CpRu(CO)2Me, (η3-allyl)Ru(CO)3Br, and (COT)Ru(CO)3, were employed to investigate the role of precursor quantum yield, ligand chemistry, and the Ru oxidation state on the deposition. To investigate the role of the substrate chemistry on deposition, carboxylic acid-, hydroxyl-, and methyl-terminated self-assembled monolayers were used. The data indicate that moderate quantum yields for ligand loss (φ ≥ 0.4) are required for ruthenium deposition, and the deposition is wavelength dependent. Second, anionic polyhapto ligands such as cyclopentadienyl and allyl are more difficult to remove than carbonyls, halides, and alkyls. Third, in contrast to the atomic layer deposition, acid-base reactions between the precursor and the substrate are more effective for deposition than nucleophilic reactions. Finally, the data suggest that selective deposition can be achieved on organic thin films by judicious choice of precursor and functional groups present on the substrate. These studies thus provide guidelines for the rational design of new precursors specifically for selective photochemical CVD on organic substrates.
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Low energy electron-induced decomposition of (η3-C3H5)Ru(CO)3Br, a potential focused electron beam induced deposition precursor with a heteroleptic ligand set. Phys Chem Chem Phys 2017; 19:13264-13271. [DOI: 10.1039/c7cp01696d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Low energy electron induced fragmentation of (η3-C3H5)Ru(CO)3Br is reported in relation to the suitability of different ligands in the design of focused electron beam induced deposition precursors.
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Aerosol-assisted chemical vapor deposition of WS2 from the single source precursor WS(S2)(S2CNEt2)2. Chem Commun (Camb) 2017; 53:7728-7731. [DOI: 10.1039/c7cc03585c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
WS(S2)(S2CNEt2)2 is a single source precursor for deposition of nanostructured WS2 above 350 °C.
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Electron Induced Surface Reactions of cis-Pt(CO)2Cl2: A Route to Focused Electron Beam Induced Deposition of Pure Pt Nanostructures. J Am Chem Soc 2016; 138:9172-82. [PMID: 27346707 DOI: 10.1021/jacs.6b04156] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Using mechanistic data from surface science studies on electron-induced reactions of organometallic precursors, cis-Pt(CO)2Cl2 (1) was designed specifically for use in focused electron beam induced deposition (FEBID) of Pt nanostructures. Electron induced decomposition of adsorbed 1 under ultrahigh vacuum (UHV) conditions proceeds through initial CO loss as determined by in situ X-ray photoelectron spectroscopy and mass spectrometry. Although the Pt-Cl bonds remain intact during the initial decomposition step, larger electron doses induce removal of the residual chloride through an electron-stimulated desorption process. FEBID structures created from cis-Pt(CO)2Cl2 under steady state deposition conditions in an Auger spectrometer were determined to be PtCl2, free of carbon and oxygen. Coupled with the electron stimulated removal of chlorine demonstrated in the UHV experiments, the Auger deposition data establish a route to FEBID of pure Pt. Results from this study demonstrate that structure-activity relationships can be used to design new precursors specifically for FEBID.
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Synthesis and evaluation of κ2-β-diketonate and β-ketoesterate tungsten(vi) oxo-alkoxide complexes as precursors for chemical vapor deposition of WOx thin films. Dalton Trans 2016; 45:10897-908. [DOI: 10.1039/c6dt01078d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
β-Diketonate and β-ketoesterate tungsten(vi) oxo-alkoxide complexes were synthesized and CVD of WOx from WO(OCH2C(CH3)3)3(tbac) was demonstrated.
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Dioxo–Fluoroalkoxide Tungsten(VI) Complexes for Growth of WOx Thin Films by Aerosol-Assisted Chemical Vapor Deposition. Inorg Chem 2015; 54:7536-47. [DOI: 10.1021/acs.inorgchem.5b01124] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Solvent Control of Surface Plasmon-Mediated Chemical Deposition of Au Nanoparticles from Alkylgold Phosphine Complexes. ACS APPLIED MATERIALS & INTERFACES 2015; 7:13384-13394. [PMID: 26036274 DOI: 10.1021/acsami.5b01918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bottom-up approaches to nanofabrication are of great interest because they can enable structural control while minimizing material waste and fabrication time. One new bottom-up nanofabrication method involves excitation of the surface plasmon resonance (SPR) of a Ag surface to drive deposition of sub-15 nm Au nanoparticles from MeAuPPh3. In this work we used density functional theory to investigate the role of the PPh3 ligands of the Au precursor and the effect of adsorbed solvent on the deposition process, and to elucidate the mechanism of Au nanoparticle deposition. In the absence of solvent, the calculated barrier to MeAuPPh3 dissociation on the bare surface is <20 kcal/mol, making it facile at room temperature. Once adsorbed on the surface, neighboring MeAu fragments undergo ethane elimination to produce Au adatoms that cluster into Au nanoparticles. However, if the sample is immersed in benzene, we predict that the monolayer of adsorbed solvent blocks the adsorption of MeAuPPh3 onto the Ag surface because the PPh3 ligand is large compared to the size of the exposed surface between adsorbed benzenes. Instead, the Au-P bond of MeAuPPh3 dissociates in solution (Ea = 38.5 kcal/mol) in the plasmon heated near-surface region followed by the adsorption of the MeAu fragment on Ag in the interstitial space of the benzene monolayer. The adsorbed benzene forces the Au precursor to react through the higher energy path of dissociation in solution rather than dissociatively adsorbing onto the bare surface. This requires a higher temperature if the reaction is to proceed at a reasonable rate and enables the control of deposition by the light induced SPR heating of the surface and nearby solution.
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Aerosol-assisted chemical vapor deposition of tungsten oxide films and nanorods from oxo tungsten(VI) fluoroalkoxide precursors. ACS APPLIED MATERIALS & INTERFACES 2015; 7:2660-2667. [PMID: 25569472 DOI: 10.1021/am507706e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Aerosol-assisted chemical vapor deposition (AACVD) of WOx was demonstrated using the oxo tungsten(VI) fluoroalkoxide single-source precursors, WO[OCCH3(CF3)2]4 and WO[OC(CH3)2CF3]4. Substoichiometric amorphous tungsten oxide thin films were grown on indium tin oxide (ITO) substrates in nitrogen at low deposition temperature (100-250 °C). At growth temperatures above 300 °C, the W18O49 monoclinic crystalline phase was observed. The surface morphology and roughness, visible light transmittance, electrical conductivity, and work function of the tungsten oxide materials are reported. The solvent and carrier gas minimally affected surface morphology and composition at low deposition temperature; however, material crystallinity varied with solvent choice at higher temperatures. The work function of the tungsten oxide thin films grown between 150 and 250 °C was determined to be in the range 5.0 to 5.7 eV, according to ultraviolet photoelectron spectroscopy (UPS).
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Abstract
Methods to convert amines to formamides are of interest due to the many uses of formamides as synthetic intermediates. These methods include stoichiometric reactions of formylating reagents and catalytic reactions with CO as the carbonyl source. This review discusses the reported stoichiometric and catalytic approaches for preparation of formamides.
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Tungsten Nitrido Complexes as Precursors for Low Temperature Chemical Vapor Deposition of WNxCy Films as Diffusion Barriers for Cu Metallization. J Am Chem Soc 2014; 136:1650-62. [DOI: 10.1021/ja4117582] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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42
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Partially fluorinated oxo-alkoxide tungsten(vi) complexes as precursors for deposition of WOx nanomaterials. Dalton Trans 2014; 43:9226-33. [DOI: 10.1039/c4dt00407h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Volatile partially fluorinated tungsten(vi) oxo-alkoxides yield tungsten oxide nanorods upon chemical vapour deposition.
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Heterobimetallic Complexes of Polypyridyl Ligands Containing Paramagnetic Centers: Synthesis and Characterization by IR and EPR. Inorg Chem 2013; 52:14116-23. [DOI: 10.1021/ic401952s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Evaluation of Multisite Polypyridyl Ligands as Platforms for the Synthesis of Rh/Zn, Rh/Pd, and Rh/Pt Heterometallic Complexes. Inorg Chem 2013; 52:5692-701. [DOI: 10.1021/ic301810y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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45
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Abstract
Carbonylation of amines in methanol in the presence of NaIO(4) produces formamide derivatives in good to excellent yields without a transition metal catalyst.
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46
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Surface Plasmon Mediated Chemical Solution Deposition of Gold Nanoparticles on a Nanostructured Silver Surface at Room Temperature. J Am Chem Soc 2012; 135:38-41. [DOI: 10.1021/ja309392x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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47
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Iron and Ruthenium Heterobimetallic Carbonyl Complexes as Electrocatalysts for Alcohol Oxidation: Electrochemical and Mechanistic Studies. Organometallics 2011. [DOI: 10.1021/om101070z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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48
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Catalytic Oxidative Carbonylation of Arylamines to Ureas with W(CO)6/I2 as Catalyst. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100657] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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49
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Electrochemical oxidation of ethanol using Nafion electrodes modified with heterobimetallic catalysts. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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50
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