Molecular Encoding at the Nanoscale: From Complex Cubes to Bimetallic Oxides

Polarz, Sebastian; Orlov, A. V.; Berg, Maurits W. E. van den; Drieß, Matthias

doi:10.1002/anie.200501212

Cited by 59 publications

(61 citation statements)

References 25 publications

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“…[15,[29][30][31][32][33][34] It is important to note that the volatility of alkyl-Zn-alkoxide precursors allows the preparation of metal-oxide nanoparticles in the gas phase using the socalled chemical vapor synthesis (CVS) process, as we demonstrated recently (see Fig. 1a).…”

Section: Sensor Preparationmentioning

confidence: 99%

Structure–Property–Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide

Polarz

Roy

Lehmann

et al. 2007

Adv Funct Materials

107

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Chemical sensing on oxide sensors is a complex phenomenon involving catalytic activity as well as electronic properties. Thus, the properties of oxide sensors are highly sensitive towards structural changes. Effects like surface area, grain size, and, in addition, the occurrence of defects give separate contributions to the current. Structure–property–function relationships can be elucidated using a combination of state‐of‐the‐art analytical techniques. It is shown, that impurity atoms in the oxide lattice influence the performance of ZnO sensors more strongly than the other factors.

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Section: Sensor Preparationmentioning

confidence: 99%

Structure–Property–Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide

Polarz

Roy

Lehmann

et al. 2007

Adv Funct Materials

107

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“…Such cubanes constitute a class of discrete compounds such as complexes based on Ni 4 O 4 or Co 4 O 4 structures, which themselves represent sections of their respective oxides. For the past four decades, these species have been studied as precursors for metal oxide nanoparticles, [7] novel magnetic materials, [8] and polymerization catalysts.[9] Coordination complexes of higher nuclearity, such as {Ni 11 }, [10] or {Co 14 } [11] frequently comprise corner-, edge-, or face-sharing aggregates of M II 4 O II 4 . As such, the generation of isostructural metalligand frameworks is especially important as they allow systematic, comparative studies of their complex magnetic phenomena and the possibility to precisely position heterometal atoms within a given architecture.…”

mentioning

confidence: 99%

Structural and Compositional Control in {M₁₂} Cobalt and Nickel Coordination Clusters Detected Magnetochemically and with Cryospray Mass Spectrometry

et al. 2007

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Full compositional and structural control in the high-nuclearity coordination clusters of transition-metal cations is a crucial synthetic target, and is motivated by these species complex electronic and magnetic properties which single them out as metalloenzyme models, [1] nanoscale containers and catalysts, [2] quantum computing components, [3] and molecular magnets.[4] Strategies for their synthesis range from the use of multifunctional organic ligands [5] to the controlled production of molecular sections of solid-state structures, such as those of transition-metal oxides.[6] In most instances the resulting metal frameworks are derived from various archetypal condensed substructures, such as (distorted) M 4 L 4 cubanes (M = metal, L = O, N, etc.). Such cubanes constitute a class of discrete compounds such as complexes based on Ni 4 O 4 or Co 4 O 4 structures, which themselves represent sections of their respective oxides. For the past four decades, these species have been studied as precursors for metal oxide nanoparticles, [7] novel magnetic materials, [8] and polymerization catalysts.[9] Coordination complexes of higher nuclearity, such as {Ni 11 }, [10] or {Co 14 } [11] frequently comprise corner-, edge-, or face-sharing aggregates of M II 4 O II 4 . As such, the generation of isostructural metalligand frameworks is especially important as they allow systematic, comparative studies of their complex magnetic phenomena and the possibility to precisely position heterometal atoms within a given architecture. However, while several almost isostructural compounds of Ni II and Co II exist, including M 4 O 4 cubane structures, because of their very similar coordination chemistry, [12] these are invariably of low nuclearity, and systems exceeding ten metal centers are rare.[13] Correspondingly, mixed-metal isostructures (i.e. structures incorporating both Ni II and Co II centers in varying ratios that are distributed over the metal framework of a coordination cluster) can be generated, yet site-specific occupation is frequently subject to binomial statistics and cannot be resolved by diffraction techniques. In such situations, as we demonstrate herein, magnetic properties can be used to discern between the possible intramolecular distribution scenarios and indicate how narrow the distribution curves are for (cocrystallizing) compositions (of the typeHerein, we demonstrate the use of templating and multifunctional ligands to facilitate the directed assembly of archetypal isostructural Ni [14]These clusters comprise three M 4 O 4 cubane units symmetrically arranged around a central templating carbonate anion and the intact clusters {M 12 } can be detected in solution using cryospray mass spectrometry.[15] Moreover, isostructural mixed Ni:Co clusters of specific composition can be accessed since the pH value of the reaction solution (i.e. an additional reaction parameter besides the stoichiometric reaction ratio of Ni and Co) is used to differentiate the relative population of the metal sites in the {M 12 } system. ...

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“…ZnO:Co lm preparation ZnO:Co nanoparticles were synthesized by solvolysis of a heterobimetallic (Co, Zn) single source precursor (SSP) mixture composed of tetranuclear cubanodic clusters of the di-2-pyridylmethandiolato (dpdH) ligand 24,25 (see ESI Fig. S1 †).…”

Section: Methodsmentioning

confidence: 99%

Optimized immobilization of ZnO:Co electrocatalysts realizes 5% efficiency in photo-assisted splitting of water

et al. 2016

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Organic solvents with varied electrophoretic mobility have been employed for deposition of nanocrystalline ZnO:Co particles onto fluorinated tin oxide supports. Evaluation of the electrochemical activity for the oxygen evolution reaction proves a clear solvent-dependence with highest activity upon deposition from acetonitrile and lowest activity upon deposition from ethanol. Analysis of the resulting layer thickness and density attributes the improved electrochemical activity of acetonitrile-prepared samples to larger film thicknesses with lower film densities, i.e. to films with higher porosity. The findings suggest that the ZnO:Co films represent an initially nanocrystalline system where the catalytic activity is predominantly confined to a thin surface region rather than to comprise the entire volume. Closer inspection of this surface region proves successive in operando transformation of the nanocrystalline to an amorphous phase during evolution of oxygen. Furthermore, less active but highly transparent ZnO:Co phases, prepared from ethanol-containing suspensions, can be successfully employed in a stacking configuration with a low-cost triple-junction solar cell. Thereby, a solar-to-hydrogen efficiency of 5.0% in splitting of water at pH 14 could be realized. In contrast, highly light-absorbing acetonitrile/acetone-prepared samples limit the efficiency to about 1%, demonstrating thus the decisive influence of the used organic solvent upon electrophoretic deposition. Stability investigations over several days finally prove that the modular architecture, applied here, represents an attractive approach for coupling of highly active electrocatalysts with efficient photovoltaic devices.

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Molecular Encoding at the Nanoscale: From Complex Cubes to Bimetallic Oxides

Cited by 59 publications

References 25 publications

Structure–Property–Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide

Structure–Property–Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide

Structural and Compositional Control in {M₁₂} Cobalt and Nickel Coordination Clusters Detected Magnetochemically and with Cryospray Mass Spectrometry

Optimized immobilization of ZnO:Co electrocatalysts realizes 5% efficiency in photo-assisted splitting of water

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Molecular Encoding at the Nanoscale: From Complex Cubes to Bimetallic Oxides

Cited by 59 publications

References 25 publications

Structure–Property–Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide

Structure–Property–Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide

Structural and Compositional Control in {M12} Cobalt and Nickel Coordination Clusters Detected Magnetochemically and with Cryospray Mass Spectrometry

Optimized immobilization of ZnO:Co electrocatalysts realizes 5% efficiency in photo-assisted splitting of water

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Structural and Compositional Control in {M₁₂} Cobalt and Nickel Coordination Clusters Detected Magnetochemically and with Cryospray Mass Spectrometry