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Artykuły w czasopismach na temat „Nanostructured Transition Metal Clusters”

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Data publikacji: 7 września 2023

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1

Reetz, Manfred T., i Wolfgang Helbig. "Size-Selective Synthesis of Nanostructured Transition Metal Clusters". Journal of the American Chemical Society 116, nr 16 (sierpień 1994): 7401–2. http://dx.doi.org/10.1021/ja00095a051.

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Scharfe, Sandra, i Thomas F. Fässler. "Polyhedral nine-atom clusters of tetrel elements and intermetalloid derivatives". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 368, nr 1915 (28.03.2010): 1265–84. http://dx.doi.org/10.1098/rsta.2009.0270.

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Homoatomic polyanions have the basic capability for a bottom-up synthesis of nanostructured materials. Therefore, the chemistry and the structures of polyhedral nine-atom clusters of tetrel elements [E 9 ] 4− is highlighted. The nine-atom Zintl ions are available in good quantities for E = Si–Pb as binary alkali metal (A) phases of the composition A 4 E 9 or A 12 E 17 . Dissolution or extraction of the neat solids with aprotic solvents and crystallization with alkali metal-sequestering molecules or crown ethers leads to a large variety of structures containing homoatomic clusters with up to 45 E atoms. Cluster growth occurs via oxidative coupling reactions. The clusters can further act as a donor ligand in transition metal complexes, which is a first step to the formation of bimetallic clusters. The structures and some nuclear magnetic resonance spectroscopic properties of these so-called intermetalloid clusters are reviewed, with special emphasis on tetrel clusters that are endohedrally filled with transition metal atoms.

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Adams, Brian D., Robert M. Asmussen, Aicheng Chen i Robert C. Mawhinney. "Interaction of carbon monoxide with small metal clusters: a DFT, electrochemical, and FTIR study". Canadian Journal of Chemistry 89, nr 12 (grudzień 2011): 1445–56. http://dx.doi.org/10.1139/v11-120.

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The adsorption of CO molecules onto small metal clusters was studied using density functional theory (DFT) calculations, and experimental electrochemical and attenuated total reflection-Fourier transform infrared spectroscopic (ATR-FTIR) techniques were used to examine CO adsorbed onto nanostructures of similar composition. The adsorption strengths and CO vibrational stretching frequencies were calculated and analyzed for clusters of the form M–CO for all of the period 4, 5, and 6 d-block transition metals. A direct link between the νCO and the population of d orbitals of the metal was observed. All possible binding sites for CO on clusters of the form Pd4–CO, Pd2Pt2–CO, and Pd2Au2–CO were determined and the corresponding adsorption energies and CO stretching frequencies were examined. Pure Pd and bimetallic PdPt and PdAu nanostructures were fabricated and used as catalysts for the adsorption and electrochemical oxidation of CO. The relative quantities of CO molecules adsorbed to surface of the catalysts decrease in the order of PdPt > Pd > PdAu, consistent with our DFT results. The location of νCO bands of CO adsorbed onto the nanostructured catalysts were determined by means of ATR-FTIR spectroscopy and were found to have values close to that predicted by DFT. This paper shows that DFT calculations on very small metal clusters Mn–CO (n ≤ 4) can be a simple but effective way of screening catalysts for their adsorbing properties.

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Bulgakov, Alexander V., Nikolay Y. Bykov, Alexey I. Safonov, Yuri G. Shukhov i Sergey V. Starinskiy. "Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition". Materials 16, nr 13 (7.07.2023): 4876. http://dx.doi.org/10.3390/ma16134876.

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Supersonic jets of metal vapors with carrier gas are promising for producing nanostructured metal films at relatively low source temperatures and high deposition rates. However, the effects of the carrier gas on the jet composition and expansion dynamics, as well as on film properties, remain virtually unexplored. In this work, the free-jet expansion of a mixture of silver vapor with helium in a rarefied regime at an initial temperature of 1373 K is investigated through mass spectrometry and direct-simulation Monte Carlo methods. Introducing the carrier gas into the source is found to result in a transition from a collisionless to a collision-dominated expansion regime and dramatic changes in the Ag jet, which becomes denser, faster, and more forward-directed. The changes are shown to be favorable for the formation of small Ag clusters and film deposition. At a fairly high helium flow, silver Ag2 dimers are observed in the jet, both in the experiment and the simulations, with a mole fraction reaching 0.1%. The terminal velocities of silver atoms and dimers are nearly identical, indicating that the clusters are likely formed due to the condensation of silver vapor in the expanding jet. A high potential of supersonic Ag-He jets for the deposition of nanostructured silver films is demonstrated. The deposited jet Ag2 dimers appear to serve as nucleation centers and, thus, allow for controlling the size of the produced surface nanostructures.

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5

Jiang, Ning, Yulong Bai, Bo Yang, Dezhi Wang i Shifeng Zhao. "Switchable metal–insulator transition in core–shell cluster-assembled nanostructure films". Nanoscale 12, nr 35 (2020): 18144–52. http://dx.doi.org/10.1039/d0nr04681g.

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MELINON, P., V. PAILLARD, V. DUPUIS, A. PEREZ, P. JENSEN, A. HOAREAU, J. P. PEREZ i in. "FROM FREE CLUSTERS TO CLUSTER-ASSEMBLED MATERIALS". International Journal of Modern Physics B 09, nr 04n05 (28.02.1995): 339–97. http://dx.doi.org/10.1142/s021797929500015x.

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In this paper the specific properties of free clusters and the formation of new cluster-assembled materials using the low energy cluster beam deposition (LECBD) technique are discussed. Recent results obtained for free clusters are summarized with special attention to new observed structures. As for the specific structures and properties of cluster-assembled materials, two main aspects are specially emphasized: the memory effect of the free cluster properties leading to the formation of new phases and the effect of the specific nanostructure of the cluster-assembled materials related to the random cluster stacking mechanism characteristic of the LECBD. These effects and the corresponding potential applications are illustrated using some selected examples: new diamond-like carbon films produced by fullerene depositions (memory effect) and grain effect on the magnetic properties of cluster-assembled transition metal films.

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7

Lu, Xizhao, Lei Kang, Binggong Yan, Tingping Lei, Gaofeng Zheng, Haihe Xie, Jingjing Sun i Kaiyong Jiang. "Evolution of a Superhydrophobic H59 Brass Surface by Using Laser Texturing via Post Thermal Annealing". Micromachines 11, nr 12 (29.11.2020): 1057. http://dx.doi.org/10.3390/mi11121057.

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To fabricate an industrial and highly efficient super-hydrophobic brass surface, annealed H59 brass samples have here been textured by using a 1064 nm wavelength nanosecond fiber laser. The effects of different laser parameters (such as laser fluence, scanning speed, and repetition frequency), on the translation to super-hydrophobic surfaces, have been of special interest to study. As a result of these studies, hydrophobic properties, with larger water contact angles (WCA), were observed to appear faster than for samples that had not been heat-treated (after an evolution time of 4 days). This wettability transition, as well as the evolution of surface texture and nanograins, were caused by thermal annealing treatments, in combination with laser texturing. At first, the H59 brass samples were annealed in a Muffle furnace at temperatures of 350 °C, 600 °C, and 800 °C. As a result of these treatments, there were rapid formations of coarse surface morphologies, containing particles of both micro/nano-level dimensions, as well as enlarged distances between the laser-induced grooves. A large number of nanograins were formed on the brass metal surfaces, onto which an increased number of exceedingly small nanoparticles were attached. This combination of fine nanoparticles, with a scattered distribution of nanograins, created a hierarchic Lotus leaf-like morphology containing both micro-and nanostructured material (i.e., micro/nanostructured material). Furthermore, the distances between the nano-clusters and the size of nano-grains were observed, analyzed, and strongly coupled to the wettability transition time. Hence, the formation and evolution of functional groups on the brass surfaces were influenced by the micro/nanostructure formations on the surfaces. As a direct consequence, the surface energies became reduced, which affected the speed of the wettability transition—which became enhanced. The micro/nanostructures on the H59 brass surfaces were analyzed by using Field Emission Scanning Electron Microscopy (FESEM). The chemical compositions of these surfaces were characterized by using an Energy Dispersive Analysis System (EDS). In addition to the wettability, the surface energy was thereby analyzed with respect to the different surface micro/nanostructures as well as to the roughness characteristics. This study has provided a facile method (with an experimental proof thereof) by which it is possible to construct textured H59 brass surfaces with tunable wetting behaviors. It is also expected that these results will effectively extend the industrial applications of brass material.

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Soldatov, Mikhail, Kirill Lomachenko, Nikolay Smolentsev i Alexander Soldatov. "Determination of the local structure in metal-complexes by combining XAS and XES". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C1521. http://dx.doi.org/10.1107/s2053273314084782.

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Nanoscale local atomic structure determines most of unique properties of novel materials without long range order. To study its fine details one has to use both computer nanodesign and advanced experimental methods for nanodiagnostics. The status of modern theoretical analysis of the experimental x-ray absorption spectra to extract structural parameters is presented. Novel in-situ technique for nanodiagnostics - extracting of 3D structure parameters on the basis of advanced quantitative analysis of X-ray absorption near edge structure (XANES) - has been developed. The possibility to extract information on bond angles and bond-lengths (with accuracy up to 0.002 nm) is demonstrated and it opens new perspectives of quantitative XANES analysis as a 3D local structure probe for any type of materials without long range order in atoms positions (all nanostructured materials and free clusters belong to this class of materials). Even more possibilities are opening by using simultaneously several experimental synchrotron based techniques: XANES and XES and/or RIXS. In the framework of these approaches, the results of recent studies of local atomic structure for several types of nanostructures including nanoclusters with different types of chemical bonding, core-shell nanoneedles and thin films of dilute magnetic semiconductors, 5d-transition metal-organic complexes, Cu1+ and Cu2+ binding sites in amyloid-β peptide, Co aqua complexes in aqueous solution, nanostructured materials for hydrogen storage and nanocatalysts based on zeolites and MOF are reported. Along with the calculations of conventional XANES and XES, we show a possibility to simulate core-to-core and valence-to-core RIXS as well. Molecular orbitals (or DOS) of metal complexes can be directly related to the peaks in XES spectra in RIXS maps. This information is essential for understanding of electronic structure of metal complexes and design of novel materials.

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9

Miras, Haralampos N., Cole Mathis, Weimin Xuan, De-Liang Long, Robert Pow i Leroy Cronin. "Spontaneous formation of autocatalytic sets with self-replicating inorganic metal oxide clusters". Proceedings of the National Academy of Sciences 117, nr 20 (5.05.2020): 10699–705. http://dx.doi.org/10.1073/pnas.1921536117.

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Here we show how a simple inorganic salt can spontaneously form autocatalytic sets of replicating inorganic molecules that work via molecular recognition based on the {PMo12} ≡ [PMo12O40]3– Keggin ion, and {Mo36} ≡ [H3Mo57M6(NO)6O183(H2O)18]22– cluster. These small clusters are able to catalyze their own formation via an autocatalytic network, which subsequently template the assembly of gigantic molybdenum-blue wheel {Mo154} ≡ [Mo154O462H14(H2O)70]14–, {Mo132} ≡ [MoVI72MoV60O372(CH3COO)30(H2O)72]42– ball-shaped species containing 154 and 132 molybdenum atoms, and a {PMo12}⊂{Mo124Ce4} ≡ [H16MoVI100MoV24Ce4O376(H2O)56 (PMoVI10MoV2O40)(C6H12N2O4S2)4]5– nanostructure. Kinetic investigations revealed key traits of autocatalytic systems including molecular recognition and kinetic saturation. A stochastic model confirms the presence of an autocatalytic network involving molecular recognition and assembly processes, where the larger clusters are the only products stabilized by the cycle, isolated due to a critical transition in the network.

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10

Dupuis, V., J. P. Perez, J. Tuaillon, V. Paillard, P. Mélinon, A. Perez, B. Barbara, L. Thomas, S. Fayeulle i J. M. Gay. "Magnetic properties of nanostructured thin films of transition metal obtained by low energy cluster beam deposition". Journal of Applied Physics 76, nr 10 (15.11.1994): 6676–78. http://dx.doi.org/10.1063/1.358165.

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Schuster, Christian, Harald Rennhofer, Heinz Amenitsch, Helga C. Lichtenegger, Alois Jungbauer i Rupert Tscheliessing. "Metal–Insulator Transition of Ultrathin Sputtered Metals on Phenolic Resin Thin Films: Growth Morphology and Relations to Surface Free Energy and Reactivity". Nanomaterials 11, nr 3 (26.02.2021): 589. http://dx.doi.org/10.3390/nano11030589.

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Nanostructured metal assemblies on thin and ultrathin polymeric films enable state of the art technologies and have further potential in diverse fields. Rational design of the structure–function relationship is of critical importance but aggravated by the scarcity of systematic studies. Here, we studied the influence of the interplay between metal and polymer surface free energy and reactivity on the evolution of electric conductivity and the resulting morphologies. In situ resistance measurements during sputter deposition of Ag, Au, Cu and Ni films on ultrathin reticulated polymer films collectively reveal metal–insulator transitions characteristic for Volmer–Weber growth. The different onsets of percolation correlate with interfacial energy and energy of adhesion weakly but as expected from ordinary wetting theory. A more pronounced trend of lower percolation thickness for more reactive metals falls in line with reported correlations. Ex situ grazing incidence small angle X-ray scattering experiments were performed at various thicknesses to gain an insight into cluster and film morphology evolution. A novel approach to interpret the scattering data is used where simulated pair distance distributions of arbitrary shapes and arrangements can be fitted to experiments. Detailed approximations of cluster structures could be inferred and are discussed in view of the established parameters describing film growth behavior.

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Babicheva, Viktoriia E., i Jerome V. Moloney. "Lattice Resonances in Transdimensional WS2 Nanoantenna Arrays". Applied Sciences 9, nr 10 (16.05.2019): 2005. http://dx.doi.org/10.3390/app9102005.

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Mie resonances in high-refractive-index nanoparticles have been known for a long time but only recently have they became actively explored for control of light in nanostructures, ultra-thin optical components, and metasurfaces. Silicon nanoparticles have been widely studied mainly because of well-established fabrication technology, and other high-index materials remain overlooked. Transition metal dichalcogenides, such as tungsten or molybdenum disulfides and diselenides, are known as van der Waals materials because of the type of force holding material layers together. Transition metal dichalcogenides possess large permittivity values in visible and infrared spectral ranges and, being patterned, can support well-defined Mie resonances. In this Communication, we show that a periodic array of tungsten disulfide (WS2) nanoantennae can be considered to be transdimensional lattice and supports different multipole resonances, which can be controlled by the lattice period. We show that lattice resonances are excited in the proximity to Rayleigh anomaly and have different spectral changes in response to variations of one or another orthogonal period. WS2 nanoantennae, their clusters, oligomers, and periodic array have the potential to be used in future nanophotonic devices with efficient light control at the nanoscale.

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13

Ku, Ruiqi, Guangtao Yu, Jing Gao, Xuri Huang i Wei Chen. "Embedding tetrahedral 3d transition metal TM4 clusters into the cavity of two-dimensional graphdiyne to construct highly efficient and nonprecious electrocatalysts for hydrogen evolution reaction". Physical Chemistry Chemical Physics 22, nr 6 (2020): 3254–63. http://dx.doi.org/10.1039/c9cp06057j.

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Coupled with the high structural stability and good conductivity, all the new 2D composite nanostructures TM₄@GDY (TM = Sc, Ti, Mn, Fe, Co, Ni and Cu) can uniformly exhibit considerably high catalytic activity for hydrogen evolution reaction.

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14

Jaksic, Jelena, Diamantoula Labou i Georgos Papakonstantinou. "Phenomena and significance of intermediate spillover in electrocatalysis of oxygen and hydrogen electrode reactions". Chemical Industry 66, nr 4 (2012): 425–53. http://dx.doi.org/10.2298/hemind110826005j.

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Altervalent hypo-d-oxides of transition metal series impose spontaneous dissociative adsorption of water molecules and pronounced membrane spillover transferring properties instantaneously resulting with corresponding bronze type (Pt/HxWO3) under cathodic, and/or its hydrated state (Pt/W(OH)6) responsible for the primary oxide (Pt-OH) effusion, under anodic polarization, this way establishing instantaneous reversibly revertible alterpolar bronze features (Pt/H0.35WO3 Pt/W(OH)6), and substantially advanced electrocatalytic properties of these composite interactive electrocatalysts. As the consequence, the new striking and unpredictable prospects both in law and medium temperature proton exchange membrane fuell cell (L&MT PEMFC) and water electrolysis (WE) have been opened by the interactive supported individual (Pt, Pd, Ni) or prevailing hyper-d-electronic nanostructured intermetallic phase clusters (WPt3, NbPt3, HfPd3, ZrNi3), grafted upon and within high altervalent capacity hypo-d-oxides (WO3, Nb2O5, Ta2O5, TiO2) and their proper mixed valence compounds, to create a novel type of alterpolar interchangeable composite electrocatalysts for hydrogen and oxygen electrode reactions. Whereas in aqueous media Pt (Pt/C) features either chemisorbed catalytic surface properties of H-adatoms (Pt-H), or surface oxide (Pt=O), missing any effusion of other interacting species, new generation and selection of composite and interactive strong metal-support interaction (SMSI) electrocatalysts in condensed wet state primarily characterizes interchangeable extremely fast reversible spillover of either H-adatoms, or the primary oxides (Pt-OH, Au-OH), or the invertible bronze type behavior of these significant interactive electrocatalytic ingredients. Such nanostructured type electrocatalysts, even of mixed hypo-d-oxide structure (Pt/H0.35WO3/TiO2/C, Pt/HxNbO3/TiO2/C), have for the first time been synthesized by the sol-gel methods and shown rather high stability, electron conductivity and non-exchanged initial pure mono-bronze spillover and catalytic properties. The underpotential spillover double layer (DL) charging and discharging properties of the primary oxide (M-OH), interrelated with the interactive self-catalytic effect of dipole-oriented water molecules, has also been proved and pointed out as the phenomenological appearance and aspect of the interactive spillover featuring intermediates. In fact, phenomenological aspects of spillover for the main reacting intermediate species in oxygen and hydrogen electrode reactions along with earned and withdrawn theoretical knowledge represent the basic concepts and aims of the present study.

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15

Hill, Jonathan P. "Chromophore Nanohybrids for Sensing and Singlet Oxygen Generation". ECS Meeting Abstracts MA2022-01, nr 14 (7.07.2022): 938. http://dx.doi.org/10.1149/ma2022-0114938mtgabs.

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Nanohybrid materials can exhibit the physical properties of their components and be used in various applications. Also, novel chromophores involving synthetically flexible molecules such as pyrazinacenes1 and porphyrins2 can be incorporated into these structures by different means in particular as MOFs or COFs, while other components include simple transition metal salts or oligonuclear metal-oxo clusters. In this work, we discuss nanohybrids materials containing oxoporphyrinogen (OxP), tetrapyrroles or fullerene as the organic component, with hybridization using respectively Ag(I) salt or oxo-Zr(IV) cluster. This yields nanohybrid materials having structures and properties due to their individual components. Highly-colored OxP is a tetrapyrrole macrocycle which can be stimulated to generate reactive singlet oxygen (1O2) under appropriate conditions (1O2 can be used for applications such as photodynamic therapy and environmental remediation). 1O2 generation by OxP undergoes significant enhancement over its unhybridized state when incorporated in nanohybrid structures, either MOFs or COFs, containing respectively oxo-Zr(IV) nodes or electron deficient linkers in porous coordination polymer nanoarchitectures. OxP-oxoZr(IV) nanohybrid can then be applied for oxidation of small molecule substrates to selected products.3 Also, C60 fullerene can be co-crystallized with silver(I) nitrate at the molecular level4 leading to a material that exhibits unique properties during its decomposition so that silver nitrate is released with concurrent deposition of highly nanostructured C60-only crystalline networks. The resulting nanohybrid material has been studied for application as slow-release antibacterial material.4 Other work includes porous materials for sensing applications. The utility of the nanohybrid approaches is demonstrated by using these examples. References: 1) G. J. Richards, J. P. Hill, Acc. Chem. Res., 2021, 54, 3228–3240. 2) M. K. Chahal, A. Liyanage, A. Z. Alsaleh, P. A. Karr, J. P. Hill, F. D'Souza, Chem. Sci., 2021, 12, 4925–4930. 3) J. Hynek, D.T. Payne, M.K. Chahal, F. Sciortino, Y. Matsushita, L.K. Shrestha, K. Ariga, J. Labuta, Y. Yamauchi, J.P. Hill, Mater. Today Chem., 2021, 21, 100534. 4) J. P. Hill, R. G. Shrestha, J. Song, Q. Ji, K. Ariga, L. K. Shrestha, Bull. Chem. Soc. Jpn., 2021, 94, 1347–1354.

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Zaporotskova, Irina V., Daniel P. Radchenko, Lev V. Kozhitov, Pavel A. Zaporotskov i Alena V. Popkova. "Theoretical study of metal composite based on pyrolyzed polyacrylonitrile monolayer containing Fe-Co, Ni-Co and Fe-Ni metal atom pairs and silicon amorphizing admixture". Modern Electronic Materials 6, nr 3 (30.09.2020): 95–99. http://dx.doi.org/10.3897/j.moem.6.3.63308.

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An urgent problem of radio engineering and radioelectronics nowadays is the synthesis of composite materials with preset parameters that can be used as electronics engineering materials. Of special interest are MW range wide-band electromagnetic radiation absorbers. Special attention is paid to materials on the basis of ferromagnetic metals that are capable of effectively absorbing and reflecting incident waves and having a clear nanostructure. Development of nanocapsulated metals will allow controlling the parameters of newly designed materials. This is achieved with the use of polymer matrices, e.g. pyrolyzed polyacrylonitrile (PPAN). This work is a theoretical study of a PPAN monolayer model containing pairs of transition metal atoms iron, nickel and cobalt which possess ferromagnetic properties, in Fe-Co, Ni-Co and Fe-Ni combinations, with silicon amorphizing admixture. We studied the geometrical structure of the metal composite systems which are modeled as PPAN molecular clusters the centers of which are voided of six matrix material atoms, the resultant defects (the so-called pores) being filled with pairs of the metal atoms being studied. The metal containing monolayer proved to be distorted in comparison with the initially planar PPAN monolayer. We plotted single-electron spectra of the composite nanosystems and characterized their band gaps. The presence of metal atoms reduces the band gap of a metal composite as compared with pure PPAN. We determined the charges of the metals and found electron density transfer from metal atoms to their adjacent PPAN monolayer atoms. We calculated the average bond energy of the test metal composite systems and proved them to be stable. The studies involved the use of the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d) basis.

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Zaporotskova, I. V., D. P. Radchenko, L. V. Kozitov, P. A. Zaporotskov i A. V. Popkova. "Theoretical studies of a metal composite based on a monolayer of pyrolyzed polyacrylonitrile containing paired metal atoms Cu—Co, Ni—Co, Ni—Cu, Ni—Fe and an amorphizing silicon additive". Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 23, nr 3 (10.11.2020): 196–202. http://dx.doi.org/10.17073/1609-3577-2020-3-196-202.

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An urgent problem of radio engineering and radioelectronics nowadays is the synthesis of composite materials with preset parameters that can be used as electronics engineering materials. Of special interest are MW range wide-band electromagnetic radiation absorbers. Special attention is paid to materials on the basis of ferromagnetic metals that are capable of effectively absorbing and reflecting incident waves and having a clear nanostructure. Development of nanocapsulated metals will allow controlling the parameters of newly designed materials. This is achieved with the use of polymer matrices, e.g. pyrolyzed polyacrylonitrile (PPAN). This work is a theoretical study of a PPAN monolayer model containing pairs of transition metal atoms iron, nickel and cobalt which possess ferromagnetic properties, in Fe–Co, Ni–Co and Fe–Ni combinations, with silicon amorphizing admixture. We studied the geometrical structure of the metal composite systems which are modeled as PPAN molecular clusters the centers of which are voided of six matrix material atoms, the resultant defects (the so-called pores) being filled with pairs of the metal atoms being studied. The metal containing monolayer proved to be distorted in comparison with the initially planar PPAN monolayer. We plotted single-electron spectra of the composite nanosystems and characterized their band gaps. The presence of metal atoms reduces the band gap of a metal composite as compared with pure PPAN. We determined the charges of the metals and found electron density transfer from metal atoms to their adjacent PPAN monolayer atoms. We calculated the average bond energy of the test metal composite systems and proved them to be stable. The studies involved the use of the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d) basis.

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Rudman, Kelly, Seyyedamirhossein Hosseini i Dennis G. Peters. "Novel Approach for the Electrosynthesis of Copper Nanoparticles". ECS Meeting Abstracts MA2019-01, nr 20 (1.05.2019): 1102. http://dx.doi.org/10.1149/ma2019-01/20/1102.

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In recent decades, nanoparticles have become a prominent research topic due to their increased catalytic activity, which is attributed to their high surface areas. Although typical synthesis methods yield highly ordered monodispersed particles, they often require harsh synthesis conditions, such as high pressure or temperatures, and the use of high-purity reagents. Moreover, these syntheses are conducted on a microliter basis and are not easily scaled-up.1 Electrochemistry offers an alternative approach for the synthesis of nanoparticles under mild conditions, since most metal reduction potentials occur at less than 2 V. One of the earliest attempts at the electrosynthesis of nanoparticles was conducted by Reetz et al.2 In their work, a palladium sheet was stripped and then reduced ions at a platinum sheet to form nanoparticles. However, these nanoparticles were not monodispersed, and therefore not ideal for catalysis. In the present work, copper nanoparticles have been synthesized in bulk via oxidation of a copper wire into a 99.7:2.3 nitromethane-water solution in the presence of an acid. A copper wire was stripped into solution and monitored via chronocoulometry. Once oxidized, copper ions were stabilized with polyethylene glycol and diffused to the cathode where they underwent electrochemical reduction with the aid of a sonic probe, which dispersed uniform-sized nanoparticles into solution. The size of these nanospheres can be controlled to range from approximately 2 nm to 250 nm due to different amounts of surfactant and copper in solution. In addition, other nanoparticle shapes, namely nanospheres and nanocubes, were obtained when the acid was changed from perchloric acid to hydrochloric acid. These changes in composition of the electrolyte allow for control over the shape and size of nanoparticles. This new method for electrosynthesis of nanoparticles allows for their shape and size control, which can be useful for large-scale, industrial purposes. References Gawande, M.B., Goswami, A., Felpin, F., Asefa, T., Huang, X., Silva, R., Zou, X., Zboril, R., Varma, R. S., Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis. Rev. 2016, 116, 3722–3811. Reetz, M.T. , Helbig W., Size-Selective Synthesis of Nanostructured Transition Metal Clusters. Am. Chem. Soc. 1994, 116, 7401–7402.

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Reetz, Manfred T., Stefan A. Quaiser, Martin Winter, Jörg A. Becker, Rolf Schäfer, Ulrich Stimming, Andrea Marmann, Roland Vogel i Toyohiko Konno. "Nanostructured Metal Oxide Clusters by Oxidation of Stabilized Metal Clusters with Air". Angewandte Chemie International Edition in English 35, nr 18 (1.10.1996): 2092–94. http://dx.doi.org/10.1002/anie.199620921.

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Whittlesey, Bruce R. "Xenophilic transition metal clusters". Coordination Chemistry Reviews 206-207 (wrzesień 2000): 395–418. http://dx.doi.org/10.1016/s0010-8545(00)00340-4.

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El-Sayed, Mostafa A. "Preface". Pure and Applied Chemistry 72, nr 1-2 (1.01.2000): vii. http://dx.doi.org/10.1351/pac20007201ii.

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This issue of Pure Appl. Chem. is devoted to papers based upon invited lectures delivered at the first IUPAC-sponsored Workshop on Advanced Material, "WAM1: Nanostructured Systems", held at the Hong Kong University for Science and Technology (HKUST) on July 14-18, 1999.The Topic Why nanostructured material? Chemists contribute to the well-being of society by exploiting the properties of the elements of the periodic table, or various forms of combination of elements, to make materials that are useful for "better living through chemistry." What happens if we use all the possible combinations that can be made? There remain great demands for developing new materials to improve our lives in fields such as medicine, energy, improving the environment, communication and transportation. Thus, we have to think of new ways to make materials that can be expected to display properties appropriate to the technologies of the new Millennium! The difference in properties of different elements and their derived compounds is a result of differences in the type of motion that their electrons can execute. This, in turn, depends on the space available for the electronic motion and the degree of its confinement. Thus, the difference between a metal, a semiconductor and an insulator is attributable to the electrons being delocalized in the first, more confined in the second and highly confined in the last. Can we physically cut material size sufficiently to change its electronic degree of confinement and thus its properties? We do know that while copper metal is a conductor, the copper atom and small molecular clusters of copper atoms are insulators. What is the size of an elemental assembly of a metal (i.e. the number of atoms in it) at which the metal-semiconductor or the metal-insulator transition occurs? Of course it depends on the length scale of the property measured. For semiconductors and metals, a large change in properties, e.g. absorption, emission, and conductivity, occurs on the nanometer length scale. Equally important, the property becomes very sensitive to the size of the nanoparticle. It can thus be expected that many variations in these properties should be observed for the same material by simply changing its size. The potential for harnessing these changes of properties in new technological applications is largely responsible for the current appeal of this exciting field. These considerations, along with our personal research interests, convinced me and Professor Joshua Jortner that it would be opportune to adopt this theme for the first IUPAC Workshop on Advanced Material. The publication of the talks given at the Workshop is timely, given the extraordinary rapidity with which new developments are taking place in the field. This collection of papers complements other recent publications of reviews on the topic of nanostructures, since it is more in the nature of a symposium-in-print and offers an assembly of short overviews and research papers which capture the dynamic associated with research at interdisciplinary interfaces, and with the development of attendant synthetic and analytical techniques. The promise of unimagined properties of nanostructured materials and of new-generation applications is an ongoing stimulus for further research, and it is hoped that this publication will contribute to the process, and furnish practitioners with new insights and inspiration. This is truly a multidisciplinary and future-targeted area of scientific research, and one which fully meets the IUPAC vision of 'new directions in chemistry', with its promise of hitherto undefined vistas of opportunity for discovery and exploitation. The WorkshopThe quality of the scientific presentations at this meeting was very high indeed. The strong international representation is in keeping with the spirit of IUPAC as well as the global nature of scientific research. The idea of the meeting was to get scientists active in advanced material from the West to interact strongly with those from the Orient. In this regard, we have succeeded as we achieved representation from seven countries from each side [China (Mainland and Hong Kong), Japan, Korea, Philippines, Singapore, and Taiwan from the Orient, and Canada, France, Germany, Israel, Spain, United Kingdom, and USA from the West]. This great accomplishment of getting us all together in such a delightful atmosphere was the result of the wise sponsorship of IUPAC and the great efforts of many people, whom I would like to acknowledge below.Acknowledgements IUPAC: for its wisdom to sponsor workshops in frontier areas of chemical research. We thank the then-IUPAC President, Prof. Joshua Jortner for cochairing the Workshop. We also thank the IUPAC Secretariat, in particular its Executive Director, Dr. John Jost, for his continuous and prompt support and Dr. Fabienne Meyers for creating and editing our web page for the Workshop and for her essential assistance in the production of this special volume. HKUST: for hosting us. We thank Dr. Nai-Teng Yu of the Chemistry Department, whose willingness to help us by accommodating the Workshop in his Department was essential; Dr. Shihe Yang whose continuous hard work and efforts made it possible to follow up the registration process; the local organizers, in particular, Prof. Leroy Chang and Ping Sheng, who supplied us with the list of participants, the names of some invited speakers and the program of a similar meeting held there recently and the Departmental staff, for their help in getting the arrangements of this workshop finalized. Georgia Tech: Dr. Clemens Burda helped in getting the workshop abstracts and putting the workshop material together, Ms. Michele Papsidero, my own secretary, spent many hours of hard work in following the process, from completing the registration list, to reminding contributors to meet different deadlines including sending the abstracts, and finally in typing and collating the whole program for the Workshop. The assistance of the USA Organizing Committee and in particular, Profs. John Zhang and Rob Whetten at Georgia Tech, was extremely useful in finalizing the scientific program. The speakers: I thank both the plenary and invited speakers who accepted our invitation, most without asking for financial support. Without them, we would not have had such an excellent scientific meeting or this valuable volume of Pure Appl. Chem.I wish to thank Professor James Bull, the editor of this special issue, for his hard work in making sure he received the manuscripts in time, for the review process of these manuscripts and for putting the whole volume together. Mostafa A. El-SayedChairman, Organizing CommitteeJulius Brown Professor School of Chemistry and Biochemistry Georgia Institute of Technology

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Wales, David J., i Anthony J. Stone. "Bonding in transition-metal clusters". Inorganic Chemistry 28, nr 16 (sierpień 1989): 3120–27. http://dx.doi.org/10.1021/ic00315a011.

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Morse, Michael D. "Clusters of transition-metal atoms". Chemical Reviews 86, nr 6 (grudzień 1986): 1049–109. http://dx.doi.org/10.1021/cr00076a005.

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Duffy, D. M., J. A. Blackman, P. A. Mulheran i S. A. Williams. "Transition metal clusters on graphite". Journal of Magnetism and Magnetic Materials 177-181 (styczeń 1998): 953–54. http://dx.doi.org/10.1016/s0304-8853(97)00757-9.

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Sawada, S., i S. Sugano. "Dynamics of transition-metal clusters". Zeitschrift f�r Physik D Atoms, Molecules and Clusters 12, nr 1-4 (marzec 1989): 189–91. http://dx.doi.org/10.1007/bf01426935.

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Kraatz, Heinz-Bernhard, Michael J. Went i John C. Jeffery. "Heteronuclear transition metal-alkyne clusters". Journal of Organometallic Chemistry 394, nr 1-3 (sierpień 1990): 167–75. http://dx.doi.org/10.1016/0022-328x(90)87231-2.

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Guirado-López, R., D. Spanjaard i M. C. Desjonquères. "Magnetic-nonmagnetic transition in fcc4d-transition-metal clusters". Physical Review B 57, nr 11 (15.03.1998): 6305–8. http://dx.doi.org/10.1103/physrevb.57.6305.

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Chia, Xinyi, Alex Yong Sheng Eng, Adriano Ambrosi, Shu Min Tan i Martin Pumera. "Electrochemistry of Nanostructured Layered Transition-Metal Dichalcogenides". Chemical Reviews 115, nr 21 (październik 2015): 11941–66. http://dx.doi.org/10.1021/acs.chemrev.5b00287.

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Plăiașu, Adriana Gabriela, Marian Cătălin Ducu, Sorin Georgian Moga, Aurelian Denis Negrea i Ecaterina Magdalena Modan. "Nanostructured transition metal oxides obtained by SPVD". Manufacturing Review 7 (2020): 12. http://dx.doi.org/10.1051/mfreview/2020009.

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The interest in the unique properties associated with materials having structures on a nanometer scale has been increasing at an exponential rate in last decade. Transition metal oxides are preferred materials for catalytic applications due to their half-filled d orbitals that make them exist in different oxidation states. Transition metal oxides show a broad structural variety due to their ability to form phases of varying metal to oxygen ratios reflecting multiple stable oxidation states of the metal ions. The Solar Physical Vapor Deposition (SPVD) presented in the paper as elaboration method is an original process to prepare nanopowders working under concentrated sunlight in 2 kW solar furnaces. The influence of the synthesis parameters on the chemical and microstructural characteristics of zinc and manganese oxides synthesized nanophases has been systematically studied using XRD, SEM and EDX.

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Zheng, Mingbo, Xiao Xiao, Lulu Li, Peng Gu, Xiao Dai, Hao Tang, Qin Hu, Huaiguo Xue i Huan Pang. "Hierarchically nanostructured transition metal oxides for supercapacitors". Science China Materials 61, nr 2 (17.10.2017): 185–209. http://dx.doi.org/10.1007/s40843-017-9095-4.

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Zhao, Jijun, Xiaoshuang Chen i Guanghou Wang. "Critical size for a metal-nonmetal transition in transition-metal clusters". Physical Review B 50, nr 20 (15.11.1994): 15424–26. http://dx.doi.org/10.1103/physrevb.50.15424.

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D'Agostino, Gregorio. "Icosahedral Order in Transition Metal Clusters". Materials Science Forum 195 (listopad 1995): 149–54. http://dx.doi.org/10.4028/www.scientific.net/msf.195.149.

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Belyakova, O. A., i Yu L. Slovokhotov. "Structures of large transition metal clusters". Russian Chemical Bulletin 52, nr 11 (listopad 2003): 2299–327. http://dx.doi.org/10.1023/b:rucb.0000012351.07223.d4.

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Pasynskii, Alexander A., i Igor L. Eremenko. "Heterometallic sulphide-bridged transition metal clusters". Russian Chemical Reviews 58, nr 2 (28.02.1989): 181–99. http://dx.doi.org/10.1070/rc1989v058n02abeh003434.

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Benito, Mónica, Oriol Rossell, Miquel Seco i Glòria Segalés. "Transition metal clusters containing carbosilane dendrimers". Journal of Organometallic Chemistry 619, nr 1-2 (styczeń 2001): 245–51. http://dx.doi.org/10.1016/s0022-328x(00)00697-5.

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Aguilera-Granja, F., S. Bouarab, A. Vega, J. A. Alonso i J. M. Montejano-Carrizales. "Nonmetal-metal transition in Ni clusters". Solid State Communications 104, nr 10 (grudzień 1997): 635–39. http://dx.doi.org/10.1016/s0038-1098(97)00380-3.

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Wang, Q., Q. Sun, J. Z. Yu i Y. Kawazoe. "Nonmetal–metal transition in Ban clusters". Solid State Communications 117, nr 11 (marzec 2001): 635–39. http://dx.doi.org/10.1016/s0038-1098(01)00009-6.

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Riley, S. J. "Chemistry of Isolated Transition Metal Clusters". JOM 40, nr 1 (styczeń 1988): 52–53. http://dx.doi.org/10.1007/bf03258019.

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Luh, Tien-Yau, Henry N. C. Wong i Brian F. G. Johnson. "Spatial notation for transition-metal clusters". Polyhedron 5, nr 5 (1986): 1111–18. http://dx.doi.org/10.1016/s0277-5387(00)84310-7.

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Smirnov, B. M., i H. Weidele. "Radiative transition mechanisms in metal clusters". Journal of Experimental and Theoretical Physics 89, nr 6 (grudzień 1999): 1030–34. http://dx.doi.org/10.1134/1.559048.

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Ceulemans, A., i P. W. Fowler. "Bonding patterns in transition metal clusters". Inorganica Chimica Acta 105, nr 1 (listopad 1985): 75–82. http://dx.doi.org/10.1016/s0020-1693(00)85248-2.

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Zhao, J. J., M. Han i G. H. Wang. "Ionization potentials of transition-metal clusters". Physical Review B 48, nr 20 (15.11.1993): 15297–300. http://dx.doi.org/10.1103/physrevb.48.15297.

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Cox, A. J., J. G. Louderback, S. E. Apsel i L. A. Bloomfield. "Magnetism in 4d-transition metal clusters". Physical Review B 49, nr 17 (1.05.1994): 12295–98. http://dx.doi.org/10.1103/physrevb.49.12295.

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Wang, Lai-Sheng, i Hongbin Wu. "Photoelectron Spectroscopy of Transition Metal Clusters". Zeitschrift für Physikalische Chemie 203, Part_1_2 (styczeń 1998): 45–55. http://dx.doi.org/10.1524/zpch.1998.203.part_1_2.045.

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Geusic, M. E., M. D. Morse i R. E. Smalley. "Hydrogen chemisorption on transition metal clusters". Journal of Chemical Physics 82, nr 1 (styczeń 1985): 590–91. http://dx.doi.org/10.1063/1.448732.

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D'agostino, Gregorio. "Phonon properties of transition-metal clusters". Philosophical Magazine B 76, nr 4 (październik 1997): 433–40. http://dx.doi.org/10.1080/01418639708241107.

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Persson, J. L., M. Andersson i A. Ros�n. "Reactivity of small transition metal clusters". Zeitschrift f�r Physik D Atoms, Molecules and Clusters 26, nr 1-4 (marzec 1993): 334–36. http://dx.doi.org/10.1007/bf01429186.

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Andersson, M., J. L. Persson i A. Rosén. "Oxidation of small transition metal clusters". Nanostructured Materials 3, nr 1-6 (styczeń 1993): 337–44. http://dx.doi.org/10.1016/0965-9773(93)90096-t.

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Whittlesey Bruce R., Whittlesey Bruce R. "ChemInform Abstract: Xenophilic Transition Metal Clusters". ChemInform 31, nr 51 (19.12.2000): no. http://dx.doi.org/10.1002/chin.200051238.

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Lei, Xinjian, Eduardo E. Wolf i Thomas P. Fehlner. "Clusters as Ligands – Large Assemblies of Transition Metal Clusters". European Journal of Inorganic Chemistry 1998, nr 12 (grudzień 1998): 1835–46. http://dx.doi.org/10.1002/(sici)1099-0682(199812)1998:12<1835::aid-ejic1835>3.0.co;2-y.

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