Metal-Oxide Based Nanoobjects: Reactivity, Building Blocks for Polymeric Structures and Structural Variety

ChemInform ◽  
2003 ◽  
Vol 34 (22) ◽  
Author(s):  
A. Mueller ◽  
S. Roy
Keyword(s):  
Metal Oxide ◽  
Building Blocks ◽  
Structural Variety ◽  
Polymeric Structures

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

scholarly journals Frontispiece: Metal Oxide Nanosheets as 2D Building Blocks for the Design of Novel Materials

2020 ◽  
Vol 26 (42) ◽  
Author(s):  
Melvin A. Timmerman ◽  
Rui Xia ◽  
Phu T. P. Le ◽  
Yang Wang ◽  
Johan E. Elshof
Keyword(s):  
Metal Oxide ◽  
Building Blocks ◽  
Novel Materials

Metal Oxide Nanocrystals: Building Blocks for Mesostructures and Precursors for Metal Nitrides

2007 ◽  
Vol 1007 ◽  
Author(s):  
Markus Niederberger ◽  
Jelena Buha ◽  
Igor Djerdj
Keyword(s):  
Metal Oxide ◽  
Metal Oxide Nanoparticles ◽  
Sol Gel ◽  
Building Blocks ◽  
Formation Mechanisms ◽  
Oxide Nanoparticles ◽  
Metal Nitride ◽  
Ordered Mesoporous Materials ◽  
Crystallite Sizes ◽  
The One

ABSTRACTSol-gel routes to metal oxide nanoparticles in organic solvents under exclusion of water represent a valuable alternative to aqueous methods. In comparison to the complex aqueous chemistry, nonaqueous processes offer the possibility to better understand and to control the reaction pathways on a molecular level, enabling the synthesis of nanomaterials with high crystallinity and well-defined and uniform particle morphologies. The manifold role of the organic species in providing the oxygen for the oxide formation and in controlling the crystal growth and the assembly properties makes it possible to tailor the morphological, structural and compositional characteristics of the final inorganic products.In addition to metal oxides with nearly spherical crystallite sizes in the range of just a few nanometers, also more complex morphologies such as nanowire bundles, nanorods or lamellar organic-inorganic hybrids of varying hierarchical complexity can be achieved in one step and without the use of any surfactants. The spherical nanocrystallites are on the one hand versatile building blocks for the fabrication of fully crystalline and ordered mesoporous materials and on the other hand suitable precursors for the synthesis of metal nitride nanoparticles.This proceeding provides an overview of the various oxidic nanoparticles synthesized via the nonaqueous and surfactant-free sol-gel approach, summarizes the most frequently found formation mechanisms, and offers some insight into the crystallization pathway of nanoparticles. Furthermore, the use of metal oxide nanoparticles as nanobuilding blocks for the preparation of nano- and mesostructures as well as their transformation into metal nitride nanocrystals will be discussed.

scholarly journals Metal/Metal-Oxide Nanoclusters for Gas Sensor Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Ahmad I. Ayesh
Keyword(s):  
Metal Oxide ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Recent Progress ◽  
Volume Ratio ◽  
Building Blocks ◽  
Special Focus ◽  
Gaseous Species ◽  
Sensor Applications ◽  
Metal Metal

The development of gas sensors that are based on metal/metal-oxide nanoclusters has attracted intensive research interest in the last years. Nanoclusters are suitable candidates for gas sensor applications because of their large surface-to-volume ratio that can be utilized for selective and rapid detection of various gaseous species with low-power consuming electronics. Herein, nanoclusters are used as building blocks for the construction of gas sensor where the electrical conductivity of the nanoclusters changes dramatically upon exposure to the target gas. In this review, recent progress in the fabrication of size-selected metallic nanoclusters and their utilization for gas sensor applications is presented. Special focus will be given to the enhancement of the sensing performance through the rational functionalization and utilization of different nanocluster materials.

scholarly journals Nanocrystalline Oxides: CdS nanowires synthesized by solvothermal method

2014 ◽  
Vol 70 (a1) ◽  
pp. C1414-C1414
Author(s):  
Nomery Hadia ◽  
Santiago Garcia-Granda ◽  
Jose Garcia
Keyword(s):  
Metal Oxide ◽  
Single Crystal ◽  
Research Programme ◽  
Building Blocks ◽  
Mediterranean Area ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
One Dimensional ◽  
Wide Range ◽  
Cds Nanowires

Recent advances in the field of nanotechnology produced an assortment of one-dimensional (1D) structures, such as nanowires and nanorods. These fascinating materials are the potential building blocks for a wide range of nanoscale electronics, optoelectronics, magnetoelectronics, or sensing devices [1]. Parallel to the success with group IV and groups III–V compounds semiconductor nanostructures, semiconducting metal oxide materials with wide band gaps are attracting attention [2-3]. The main aim of this communication is to report our results on the application of several new techniques, particularly the use of hydrothermal synthesis, to fabricate single crystal one-dimensional nanostructured materials, study their growth processes, understand the growth mechanisms and investigate their physical properties. A wide range of remarkable features are then presented, to cover a number of metal oxides, such as ZnO, Sb2O3, CdS, MgO, α-Fe2O3, or TiO2, describing their structures, optical, magnetic, mechanical and chemical sensing properties. These studies constitute the basis for developing versatile applications based on metal oxide 1D systems as well as highlighting the current progress in device development. To exemplify, the as-prepared CdS nanowires have average 28 nm in diameter and length up to several micrometres. The direct band gap of the CdS nanowires is 2.56 eV calculated by the UV-vis absorption spectra. The PL spectrum has two distinct emission bands at 502 nm and 695 nm, which are associated with the near-band-edge emission and defect emission, respectively. These synthesized single-crystal CdS nanowires have a high potential in the optoelectronic applications of nanolasers, solar cells, lighting-emitting diodes or photodetectors. Acknowledgments: Erasmus Mundus MEDASTAR (Mediterranean Area for Science, Technology and Research) Programme, 2011–4051/002–001-EMA2, Spanish MINECO (MAT2010-15094, Factoría de Cristalización – Consolider Ingenio 2010) and ERDF.

Expanding the Hierarchy of Metal-Oxide Building Blocks from Fragments via Clusters to Networks: A ∞ 2 [({Mo17(NO)2}3{MoV 2}3{FeIII}6)(FeII 1.5)]-Type Layer Compound

2005 ◽  
Vol 16 (3) ◽  
pp. 391-396 ◽  
Author(s):  
Achim Müller ◽  
Sergei Talismanov ◽  
Paul Kögerler ◽  
Hartmut Bögge ◽  
Marc Schmidtmann ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Building Blocks ◽  
Layer Compound ◽  
Type Layer

scholarly journals Synthesis, Sorption and Metallochromy Properties of Organosilicon Derivatives of 1-Acetylguanidine

2021 ◽  
Vol 13 (1) ◽  
pp. 78-87
Author(s):  
E.N. Oborina ◽  
◽  
A.M. Nalibayeva ◽  
V.G. Fedoseeva ◽  
I.A. Ushakov ◽  
...  
Keyword(s):  
Noble Metals ◽  
Large Scale ◽  
Condensation Reaction ◽  
Building Blocks ◽  
Test Methods ◽  
Metal Extraction ◽  
Composition And Structure ◽  
Complex Test ◽  
Derivatives Of ◽  
Polymeric Structures

Increased interest in carbofunctional organosilicon monomers (silanes) and polymers (silsesquioxanes) is associated with the fact that these compounds are promising reagents and building blocks, materials for micro-electronics, agriculture and medicine, complexones, catalysts, and efficient sorbents. Thus, functional polysilsesquioxanes surpass mineral and organic sorbents in sorption properties. Moreover, they have the highest chemical and thermal stability. Along with sorption activity carbofunctional organosilicon compounds of both monomeric and polymeric structures can possess metallochromic properties. All this paves the way for the large-scale development of analytical systems for the creation of new complex test methods for the determination, concentration and separation of metals from solutions. In the present study the functional monomer N-[3-(triethoxysilyl)propyl]acetylguanidine 1 was synthesized by the condensation reaction of 1-acetylguanidine and 3-triethoxysilyl-propylamine. Poly-N-[3-silsesquioxanyl) propyl]acetylguanidine 2 was obtained by hydrolytic polycondensation of compound 1. The composition and structure of compounds 1 and 2 were confirmed by IR and 1H NMR spectroscopy, as well as by elemental analysis. Polymer 2 was studied as a sorbent for ions of heavy metals, such as Hg (II), and noble metals Ag (I), Au (III), Rh (II), Pd (II), Pt (IV) from solutions of their salts in hydrochloric or nitric acid. For polymer 2, the values of static sorption capacities have been calculated. The latter depend on the nature of the metal and have values from 78 mg/g (for platinum) to 366 mg/g for rhodium. The graphs of the degree of metal extraction depending on the sorption time and acid concentration have been plotted. A sorption mechanism is proposed, which is realized due to the chelate interaction of the metal cation (M+) with the amide groups of compounds 1 and 2. The interaction of monomer 1, in the form of indicator paper, and polymer 2, in the powder form, with salts of the studied metals is accompanied by intense specific coloration (metallochromy). Color tables of the samples after their contact with the Ag (I), Au (III), Pd (II), Pt (IV), Rh (III), Hg (II) salts are given.

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