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Metal–organic frameworks (MOFs) have diverse structures and compositions, inspiring the boundless enthusiasm and creativity of researchers in the field of electromagnetism. The synthesis of MOF-derived nanomaterials for electromagnetic wave (EMW) absorption with ultrathin matching thickness (below 1.6 mm) is highly desired and challenging. Here, we demonstrate a general synthesis strategy for metal (Co, Ni, Fe)-based MOFs, which transformed into metal/metal-oxide nanoparticles (NPs) of being coated by nitrogen (N)-doped graphitized carbon. The obtained carbon-coated NPs show excellent EMW absorption properties. Specifically, Co-based MOFs are pyrolyzed into rhombic dodecahedrons with numerous ultrasmall Co NPs coated by N-doped carbon (Co-NC core–shell NPs). The synthesized Co-NC core–shell NPs possess a unique porous structure, abundant defects, and doped N heteroatoms, resulting in good magnetic loss (eddy current loss), dielectric loss (multiple reflections, interfacial polarization, conduction loss), and impedance matching. Therefore, the Co-NC core–shell NPs exhibit an excellent EMW absorption property with a very strong reflection loss of −56.5 dB at a matching thickness of only 1.58 mm. The effective absorption bandwidth (EAB) is 4.4 GHz. In addition, the EAB between 1 and 5 mm in thickness is up to 13.2 GHz, which already includes all C bands and X bands, even the absolute S bands and Ku bands. This work provides an avenue to design high-performance EMW absorption devices based on MOF-derived nanomaterials. [ABSTRACT FROM AUTHOR]

Gold nanorods and bipyramids are synthesized by using the seed-mediated approach in aqueous cetyltriethylammonium bromide (CTEAB) solutions in the presence of silver nitrate. Transmission electron microscopy characterizations have revealed that the gold nanorods grown from both types of gold nanoparticle seeds are single-crystalline and that the gold bipyramids are penta-twinned.

The use of transparent silica-block copolymer composites as host matrices for optically limiting dye molecules is studied. The resulting increase in dye solubility and photophysical stability is examined.

Five commercial poly (ethylene oxide)/poly (butylene oxide) (PEO/PBO) triblock copolymer surfactants are used as structure-directing agents to synthesize mesoporous silica under acidic conditions by using powder X-ray diffraction (XRD), nitrogen adsorption analysis, and transmission electron micrographs (TEM). CMC of block copolymer surfactant is revealed to be a powerful criterion for the experimental design of synthesis of ordered mesoporous materials.

The combination of electrostatic affinities and hydrogen bonding between the poly-L-lysine and the critic acid-functionalized QDs creates a zone of water exclusion around each nanoparticle. Excess number of positive charges associated with the polymer relative to the number of carboxylic acid groups (pK3) is required for these vesicles to form and therefore the initially negative charged pK3 carboylic acid group of the citrate-coated QDs is effectively neutralized after reaction with the polypeptide.

The isomorphic substitution and postsynthesis introduction of zirconium metal centers into the cubic phase of mesoporous silica are described. The process involves hydrothermal Si/Zr coprecipitation and postsynthesis functionalization of surface silanols with zirconium propoxide. Results from nitrogen sorption and X-ray powder diffraction experiments show that the structure, high surface area and narrow pore size distribution are maintained. Grafting with zirconium propoxide yields the most isolated metal species.

The synthesis of new mesoporous silica structures using low molecular weight nonionic ethylene oxide surfactants and poly(alkylene oxide) block copolymers in acid media is described. Results showed that the selected surfactant species not only influence the structure of ordered mesoporous silica, each surfactant type also plays a role in the formation of a specific mesostructured silica phase. It was also observed that the silica formed were highly ordered and thermally stable even in boiling water.

Ordered, lamellar, iron oxide/surfactant composites with varied iorn oxide layer thicknesses, were synthesized and characterized. Controlled precipitation and hydrolysis of aqueous iron cations was used to prepare the new materials, with redox chemistry to alter the iron oxide solubility. X-ray diffraction determined the layered structre of the composites, produced with about three to almost 20 A of iron oxide, alternated with surfactant bilayers.

The syntheses and characterizations of chiral tetrahedral cobalt phosphate compounds: MCoPO4 (M=Na, K, NH4, Rb) as well as the different types of framework structures have been described. One of the structures has the same topology as the zeolite ABW framework and the other cobalt phosphate can be viewed as a hybrid of tridymite and ABW frameworks. The cobalt phosphate compounds can be synthesized under hydrothermal conditions and their frameworks are more flexible than aluminosilicate in adapting cations of different sizes.

Different analogs of the Na3(ABO4)3.4H2O sodalite framework are synthesized and dehydrated with the retention of structure. Crystals of GaGe-SOD and AlGe-SOD systems are synthesized to solve space groups by X-ray diffraction. The size of tetrahedral atoms has little influence on the formation of the framework. Dehydration becomes difficult with increase in size of the tetrahedral atom. Thermogravimetric methods and in-site variable-temperature X-ray studies are employed to determine dehydration eligibility.

The synthesis, structure and properties of two new phases, a zincophosphate and a berylloarsenate are reported. The phases are non-zeolitic and contain 1-dimensional chains with tetrahedral 3-rings as building blocks. The crystal structure of Be2AsO4OH.4H2O shows a tetrahedron network connected by H-bonding of hydroxide groups and water molecules. Two types of ring linkages were observed: a 3-ring lying in the bc plane and adjacent 3-rings in 1-dimensional stacks connected by Be(1)-O(1)/O(2)-As(1) and Be(2)-O(3)/O(4)-As(1) links.

The characterization of zinc diethyl phosphate (Zn(O2P(OC2H5)2)2), which is prepared from the reaction of ZnO, triethyl phosphate and water, is presented. The complex consists of a one-dimensional chainlike structure with tetrahedral ionic cores surrounded by hydrocarbon coatings. These hydrophobic chains interact via van der Waals' attractive forces, which is characteristic of polymers. However, these chains are aligned, forming a normal, sharply diffracting crystal.

Nonstoichiometric silver,sodium bromosodalites, which allow the control of filling both silver and X ions in a sodalite host lattice in a sytematic manner to fabricate Na4-nAgnX semiconductor-component clusters, were synthesized. Spectrum analysis indicate that these halosodalites form a solid solution of Na3-mAgm clusters in anion-free beta cages interspersed with Na4-nAgnX clusters. In addition, the clusters are statistically distributed throughout the lattice.

Sodium sodalites of the composition Na8X2(SiAlO4)6, where X = Cl1-, Br1- and I1-, were prepared by a low-temperature hydrothermal synthesis. The Na1+ ions were replaced with Ag1+ ions via AgNO3 melt and hydrothermal aqueous exchanges. Results showed that unit cell sizes of class A sodalites are influenced by silver concentration andhalide type. Low silver concentrations result in short Ag-X distances, while high Ag1+ concentrations up to complete exchange result in a sodalite lattice possessing an expanded silver halide.

A magnesiothermic reduction synthesis approach is described for direct conversion of Si[O.sub.2]/C composite nanostructures to corresponding SiC materials without losing their nanostructure morphologies. An ordered hierarchical macro-mesoporous SiC material is prepared and the pseudomorphic transformation is regarded as a general synthesis method for different kinds of SiC nanostructures, which is extended to other metal carbide materials as well as TiC.

Mesoporous mixed metal oxide (K-Cu-Ti[O.sub.2]) catalyst is capable of highly selective, gas-phase benzyl alcoholbenzaldehyde transformation under low temperatures. The low-temperature reaction conditions and integration of K and Cu(I) components into the Ti[O.sub.2] matrix are very important for the stabilization of an active Cu(I) oxidation state and resultant stable, excellent catalytic performance.

An unprecedented type of ordered mesoporous material with a hexagonally pillared lamellar (HPL) structure (P[6.sub.3]/mmc) that could be synthesized via a phase transformation from a lamellar mesophase by hydrothermal reaction in the presence of an organosilica precursor and a high concentration of a designed Gemini surfactant ([Gem.sub.16-3-16]) that have a large g value is reported. The GMO-HPL which have a unique three-dimensional periodic structure with two-dimensionally connected pore channels running between the framework layers, provides a fascinating topological link between the lamellar and columnar (2D hexagonal) mesophases.

A facile nonaqueous synthetic route is described for preparing anatase nanosheets with exposed {001} facets and high-quality rhombic-shaped anatase nanocrystals with a large percentage of exposed {010} facets. The nanostructured Ti[O.sub.2] has displayed conspicuous activity in the photocatalytic degradation of organic contaminants.

The development and the mechanisms involved in one- and two-photon induced polymerization of methylmethacrylate using colloidal CdS semiconductor quantum dots (QDs) is presented. The efficiency of the photopolymerization process is shown to highly increase by the co-initiators.

A large-scale and versatile synthetic approach is described for obtaining porous carbon and porous carbon/hollow metal oxide microfibers with uniform and tunable pore sizes and well-defined carbon/metal oxide interfaces by using an ice-templating strategy. These porous carbon and carbon/metal oxide composite fibers are shown to be promising candidates for a wide range of applications.

The article discusses the reversible addition fragmentation chain transfer (RAFT) process, which is commonly used for the synthesis of various well-defined, double hydrophilic block copolymers and nanostructured hydrogels.

Methods for synthesizing mesostructured inorganic oxides that are not based on a silicate framework are described. The critical aspects of mesostructure synthesis derived from experiments on both silicate and non-silicate materials are reviewed.

A general strategy to prepare oxide-supported metal nanoparticle catalysts that could be used in acidic and basic oxides was developed. The method was successfully applied to develop green, efficient gold catalysts like the selective oxidation of ethanol by oxygen.

A facile one-step one-phase synthetic route to achieve a variety of metallic nanoparticles by using amine-borane complexes as reducing agent is reported. The use of amine-borane complexes as reducing agents and thiols as capping ligands is essential to the synthetic route reported.

A high-optical-quality titania-based mesostructured film with cubic or 2D-hexagonal symmetry is fabricated. The results revealed that trifluoroacetate (TFA) coordinates the titanium center and forms a stable complex that is subsequently organized by the block copolymer species into ordered mesostructures.

Several examples of composite titania-based nanostructured materials exhibiting cooperative functionalities between different active components are presented. The fabrication of these integrated composite materials is based on one-pot supramolecular templating techniques combined with acidic sol-gel chemistry.

Most organisms consist of a functionally adaptive assemblage of hard and soft tissues. Although little s known about how nature relieves these stresses, it is generally agreed that fundamental insights about molecular adaptation at hard/soft interfaces could profoundly influence how one thinks about biomaterials.

The formation SiO2 / gold nanoparticals based hollow microspheres with the help of dye-tagged poly(L-lysine) (PLL) is described. Structural analysis indicates that the PLL is located in the interior of the hollow sphere within the silica shell wall.

A new type of Gemini surfactant containing a siloxane moiety, which can yield highly stable mesoporous metal oxides after the removal of the surfactant via the nano-propping pathway, is described. Structures of the Gemini surfactant and a schematic diagram for the nano-propping pathway are presented.

The hexagonally organized mesoporous silica nanofibers are synthesized. These nanofibers possess a circular or longitudinal pore architecture, which can be readily controlled via the synthesis.

Energy transfer between the organic laser dyes coumarin 485 and pyrromethene 567 was investigated in mesostructured silica/block copolymer thin films. Investigations into amplified spontaneous emission revealed that the donor/acceptor system resulted in full gain narrowing at significantly lower concentrations than systems without a donor.

The development of patterned microlaser arrays formed from rhodamine 6G (R6G)-doped mesotructured silica using the amphiphilic triblock copolymer is presented. The results concluded that the high quality mesostructured waveguides can be prepared rapidly by combining soft lithographic methods with acidic solgel chemistry in the presence of structure-directing amphiphilic triblock copolymers.

A novel strategy is reported for controlled preparation of cross-linked polymeric nanoparticles (NPs). The cross-linkers with enhanced reactivity and controlled microwave reaction procedures have proved to be powerful tool for the synthesis of cross-linked, functionalized NPs under high solids content and surfactant-free conditions.

The tunable invitro hemostatic activity of high-surface-area hemostatic bioactive glass (BG) is evaluated with Thromboelastograph, a standard medical instrument for quantifying viscoelasticity changes of blood during thrombosis and fibrinolysis. The investigation of the effect of particle morphology, and preliminary result reveal that size and shape are key clotting parameters.

A simple approach for the selective shortening of single-crystalline Au NRs (gold nanorods) by mild oxidation with environmentally benign oxygen is reported. This shortening method could be used to produce Au NRs of any desired aspect ratio with narrow size distributions within the limit of that possessed by starting NRs.