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Synthesis Conditions (synthesis + condition)
Selected AbstractsRobust quadratic performance for time-delayed uncertain linear systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 2 2003Fen WuArticle first published online: 20 DEC 200 Abstract In this paper, the analysis and control synthesis problems were studied for a general class of uncertain linear systems with variable time delay. It is assumed that the structured time-varying parametric uncertainties enter the system state-space description in a linear fractional fashion. The generic quadratic performance metric encompasses many types of dynamic system performance measure. In the context of delay-independent stability, it was shown that the analysis and state-feedback synthesis problems for such time-delayed uncertain systems can be formulated equivalently as linear matrix inequality (LMI) optimization problems using the mechanism of full block multipliers. However, the solvability condition to output-feedback problem was given as bilinear matrix inequality (BMI), which leads to a non-convex optimization problem. A numerical example is provided to demonstrate the advantages of newly proposed control synthesis condition for time-delayed uncertain systems over existing approaches. Copyright © 2002 John Wiley & Sons, Ltd. [source] Morphology studies of doped polyaniline micro/nanocomposites containing TiO2 nanoparticles and Fe3O4 microparticlesPOLYMER COMPOSITES, Issue 7 2009Sook-Wai Phang To produce polyaniline (PAni) nanodevices that display excellent microwave absorbing behaviors, novel hexanoic acid-doped PAni micro/nanocomposites containing TiO2 nanoparticles and Fe3O4 microparticles (PAni/HA/TiO2/Fe3O4) were prepared by template-free method, particularly to improve the dielectric and magnetic property of PAni. PAni/HA/TiO2/Fe3O4 synthesized at different polymerization temperatures and polymerization time by various TiO2 and Fe3O4 contents, and particles size of TiO2 were prepared. The aim of this research is to investigate the effect of synthesis condition on the morphology behaviors of nanorods/tubes. The resulted nanorods/tubes indicated that PAni micro/nanocomposites exhibited polymerization through elongation. PAni micro/nanocomposites synthesized at 0°C resulted in large amounts of nanorods/tubes compared with those synthesized at subzero temperature and above 0°C. PAni/HA/TiO2 and PAni/HA/TiO2/Fe3O4 synthesized using TiO2 with diameter (particles size) 180 nm resulted in large amounts of nanorods/tubes (diameter nanorods/tubes = 80,140 nm) compared with those synthesized using TiO2 with diameter of 30 and 6 nm. Increasing TiO2 and Fe3O4 content above 10% will significantly reduce the amount of nanorods/tubes. In conclusion, synthesis parameters mentioned above are the significant factors that might affect the morphology behaviors of PAni nanostructures. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Crystal growth and structural refinement of NaMn7O12CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10-11 2005E. Gilioli Abstract We report the crystal growth and the structural refinement of NaMn7O12, a manganite having a double perovskite structure. As in many similar compounds, there is coexistence of Mn3+ and Mn4+ but in this material they orderly occupy different sites for crystallographic reasons. Therefore, this peculiar structure can be considered as a model system for studying complex mechanisms such as charge, orbital and spin ordering. High purity bulk samples and "large" single crystals are needed to study tiny modifications in the crystallographic and magnetic structures associated to the ordering phenomena. Almost single phase (more than 96% pure) and single crystals (up to about 150 µm) of NaMn7O12 were synthesized by solid state reaction under pressure in a multi-anvil apparatus. Single crystal x-ray diffraction and SEM analysis have been used to characterize the crystals. The structure refinement indicates that NaMn7O12 crystallizes in the cubic Im3 space group, with a = 7.312 Å and Z = 2. Further studies are in progress to optimize the synthesis conditions, in order to grow larger crystals. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Frameworks by Solvent-Free Synthesis of Rare Earth Chlorides with Molten 1,3-Benzodinitrile and Tailoring of the Particle Size: ,3[LnCl3{1,3-C6H4(CN)2}], Ln = Y, Dy, Ho, Er, YbEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2010Christoph J. Höller Abstract The solvent-free melt reactions of anhydrous rare earth trichlorides with molten 1,3-benzodinitrile [1,3-C6H4(CN)2, C8H4N2] result in isophthalonitrile frameworks of the rare earth elements. The particle size of the products can bevaried from the millimeter to the nanometer scale (down to 50,400 nm) depending on the synthesis conditions. Thus, these network structures are among the very few coordination polymers that can be synthesized as nanoparticles. A constitution of 1:1 concerning LnCl3/1,3-C6H4(CN)2 is found for Y (1), Dy (2), Ho (3), Er (4), and Yb (5) in isotypic,3[LnCl3{1,3-C6H4(CN)2}]. The ligand 1,3-C6H4(CN)2 functions both as chemical scissors and replaces chloride linkages by degrading the rare earth chloride structures, and subsequently forms new 3D-framework structures. They consist of strands of chlorido-coordinated lanthanide atoms, which are linked in two dimensions by 1,3-C6H4(CN)2 molecules. Compounds 1,5 were obtained as single crystals from the melt reaction, and their crystal structures were determined by single-crystal X-ray analysis. They can also be obtained as nanocrystalline materials from a ball mill treatment, identified by electron microscopy (REM) and EDX analysis. [source] Assembly and Formation of Biomorphic Tin Dioxide by a Biomimetic Sol,Gel Approach Involving GlycoproteinEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2007Qun Dong Abstract Three diverse layers of eggshell membrane (ESM) were introduced in a biogenic sol,gel technique for the synthesis of hierarchical SnO2 nanomaterials with corresponding configurations. Typically, the biomorphic replication of the interwoven inner eggshell membrane was systematically investigated by controlling synthesis conditions such as pH value, dipping time, and calcination temperature. The as-prepared SnO2 tubes consisting of interconnected 5-nm nanocrystallite units were successfully interwoven into ESM-morphic films. Herein, the biomaterial ESM served both as the physical substrate and the functional macromolecule template to realize the precision replication, by the interactions between ESM macromolecules (containing carboxyl, hydroxy, amino groups, etc.) and Sn colloid ingredients. Moreover, some biomacromolecules also acted as the surfactant to yield small-scaled and well-distributed SnO2 nanocrystallites based on the strong bondage of short-chained amino acids within ESM glycoprotein with SnO2 nuclei. This technique can be attributed to a biomimetic sol,gel process and is widely applicable to the synthesis of other functional material systems. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Spheres of Microporous Titanosilicate Umbite with Hierarchical Pore Systems,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2008Víctor Sebastián Abstract Micrometric polycrystalline spheres of up to 1,mm diameter of microporous titanosilicate K2TiSi3O9·H2O with umbite structure have been prepared without the use of organic structuring agents. These spheres are organized as micro/macroporous hierarchical materials with macropores in the 0.2,1.4,µm range of average size, showing that intraparticular resistance to water transport is not limiting. Also, similar ion exchange performance can be observed in the Ti-umbite spheres and in the single crystals obtained under the same synthesis conditions. [source] Effects of Structural Variation on the Photocatalytic Performance of Hydrothermally Synthesized BiVO4,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2006J. Yu Abstract Highly crystalline monoclinic scheelite BiVO4 powders are synthesized from aqueous Bi(NO3)3 and NH4VO3 solutions over a wide range of pH by a hydrothermal process. BiVO4 powders with various morphologies, surface textures, and grain shapes are selectively synthesized by adjusting the pH. The dependence of the Raman peak position and intensity on the synthesis conditions indicates that the symmetry distortions in the local structure of the synthesized BiVO4 are affected by the preparation conditions. These variations in the local structure result in the modification of the electronic structure of BiVO4, which results in a blue-shift in the UV-vis absorption spectrum of hydrothermally synthesized BiVO4 in comparison with a well-crystallized sample prepared by homogeneous coprecipitation. The photocatalytic activities for O2 evolution from an aqueous AgNO3 solution under visible-light irradiation are strongly dependent on the pH used in the synthesis. The differences in the photocatalytic activities between BiVO4 samples prepared under various conditions is attributed to the degree of structural distortion, leading to differences in the mobility of photogenerated holes formed in the valence band, which consists of Bi,6s and O,2p orbitals. [source] Crosslinked Bicontinuous Cubic Lyotropic Liquid-Crystal/Butyl-Rubber Composites: Highly Selective, Breathable Barrier Materials for Chemical Agent Protection,ADVANCED MATERIALS, Issue 24 2006X. Lu A breathable material that can act as a barrier to chemical agents is presented. The material is composed of butyl rubber and a crosslinkable lyotropic liquid crystal. Under the right synthesis conditions, a cubic phase with the desired selectivity properties results (see figure). The material is highly permeable to water vapor, but strongly impermeable to a mustard gas simulant. Application of the material for effective personal protection against such chemical agents is envisaged. [source] Extended anti-windup control schemes for LTI and LFT systems with actuator saturationsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 15 2004Fen Wu Abstract In this paper, the popular anti-windup control scheme will be extended in two important directions. The first scenario is the control of LTI systems subject to actuators with both magnitude and rate constraints. The second case of extension is LFT systems with input saturations. Based on the extended Circle criterion, we will develop convex anti-windup control synthesis conditions in the form of LMIs for each class of systems. The explicit anti-windup controller formula are also provided to facilitate compensator construction. The effectiveness of proposed anti-windup control schemes will be demonstrated using a flight control example. Copyright © 2004 John Wiley & Sons, Ltd. [source] Influence of the matrix porosity on the synthesis and adsorption behavior of dithiocarbamate styrenic resins toward zinc(II) and cadmium(II) ionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Priscila A. da Costa Abstract The dependence of the adsorption behavior toward Zn2+ and Cd2+ on the synthesis conditions of dithiocarbamate styrenic resins was investigated. We synthesized styrene,divinylbenzene copolymers with different kinds of porous structures by varying the divinylbenzene (DVB)-to-styrene ratio and the dilution degree of the monomers with n -heptane. The porous structure of these materials was characterized. The introduction of the dithiocarbamate moiety on the copolymers followed a synthetic pathway based on the nitration reaction, reduction of the nitro group to the amino one, and finally, the addition of the amino group to CS2. All of the synthesis steps were monitored by Fourier transform infrared spectroscopy. Only the addition reaction to CS2 was greatly influenced by the copolymer porosity. The effect of the dilution degree on the reaction extension was more pronounced than the effect of the DVB content. The more porous materials with higher dithiocarbamate contents adsorbed a higher amount of ions in a faster way, with Zn2+ being preferable over Cd2+ ions. The difference between the Zn2+ and Cd2+ adsorption rates was enhanced with the copolymer porosity, and also enhanced was the difference between the amounts of ions adsorbed by the copolymer; this suggested that the selectivity toward these ions could be controlled by the copolymer porous structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis of hafnium tungstate by a CO2 laser and its microstructure and Raman spectroscopic studyJOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2008E. J. Liang Abstract Densely packed hafnium tungstate blocks were synthesized by rapid solidification with a CO2 laser. It is shown that the optimum synthesis conditions for HfW2O8 are around 700 W laser power and 1 mm/s scan speed. Scanning electron microscopy (SEM) observation shows that the blocks consist of oriented nano-threads/rods that grew horizontally on the surface region and vertically in the interior. The orientations of the nanostructures are governed by the heat transfer directions on the surface and in the interior. Raman spectroscopic and X-ray diffraction studies show that the samples solidified in the cubic structure with minor contents of the orthorhombic phase. This is explained by a compressive stress induced during the rapid solidification process due to a sudden drop of temperature of the molten pool to the ambient. The stress is estimated to be about 0.6 GPa by comparison with high-pressure Raman study. Some specific Raman bands appear in the samples synthesized with the laser synthetic route but not in the sample by solid-state reaction. Copyright © 2008 John Wiley & Sons, Ltd. [source] Optimisation of kojic acid monolaurate synthesis with lipase PS from Pseudomonas cepaciaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2002Chee-Shan Chen Abstract To improve the instability of kojic acid in food and cosmetic use, the esterification of kojic acid catalysed by lipase from Pseudomonas cepacia (Amano PS) to synthesise kojic acid monolaurate (KAML) was investigated in this study. Response surface methodology (RSM) with a five-level/five-factor central composite rotatable design (CCRD) was employed to evaluate the effects of synthesis parameters such as reaction time (8,24,h), temperature (35 55,°C), enzyme amount (10,50%), substrate molar ratio of lauric acid to kojic acid (1:1,3:1) and added water content (0,20%) on the percentage molar conversion to KAML by direct esterification. Reaction time and added water content were the most important variables, while substrate molar ratio had less effect on percentage molar conversion. Based on canonical analysis and ridge maximum analysis, optimal synthesis conditions were reaction time 19,h, temperature 44,°C, enzyme amount 38%, substrate molar ratio 2:1 and added water content 10%. The predicted value was 85% and the actual experimental value 82% molar conversion. © 2002 Society of Chemical Industry [source] Synthesis of Polypyrrole Using Benzoyl Peroxide as a Novel Oxidizing AgentMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 3 2006Chandrasekaran Saravanan Abstract Summary: Benzoyl peroxide is used as an oxidizing agent for the first time in the synthesis of conducting polypyrrole. Synthesis of polypyrrole is commonly performed by chemical oxidative polymerization using water-soluble oxidizing agents. In this work, polypyrrole was prepared using organic solvent-soluble benzoyl peroxide as an oxidizing agent in the presence of p -toluenesulfonic acid (p -TSA) and sodium lauryl sulfate (SLS) surfactant via the inverted-emulsion-polymerization technique. During polymerization, SLS is converted to dodecyl hydrogensulfate (DHS) and incorporated on to polypyrrole along with p -TSA dopant, indicating SLS is acting as emulsifier as well as dopant. The influence of synthesis conditions such as the duration of the reaction, the temperature, the concentration of the reactants, etc., on the properties of polypyrrole was investigated to determine the optimum conditions for the synthesis of polypyrrole salt. Polypyrrole was obtained in a reaction time of 1 h with high yield (154 wt.-% with respect to pyrrole used) and good conductivity (2 S,·,cm,1). The conductivity of polypyrrole-salt was found to be nearly the same even after seven months of storage at ambient temperature (1.7 S,·,cm,1). [source] Effect of Surface Modification on the Synthesis of Pore-Filling Polymeric Monoliths in Microfiltration Membranes Made from Poly(propylene) and Poly(ethylene terephthalate)MACROMOLECULAR MATERIALS & ENGINEERING, Issue 3 2007Abdus Salam Abstract The effect of pre-modification on the interaction of macroporous substrates (membranes) with mainly micro- and mesoporous polymer monoliths has been studied. Bulk, porous polymer monoliths were synthesized to optimize the synthesis conditions and their pore morphology, and the data were used as benchmark for this study. Pre-modification of the entire pore surface of PP microfiltration membranes and PET track-etched membranes by UV-initiated grafting with PEGMA was performed using well-established methods, including coating with the photo-initiator, benzophenone. Subsequently, these membranes were functionalized by filling the pores with porous polymer monoliths from MAA and EDMA and compared with membranes that had been functionalized without the pre-modification step. The materials were characterized mainly by the degree of grafting, SEM and by the gas-adsorption-isotherm method. The DG values, after composite-membrane preparation under identical conditions, were not influenced by the pre-modification. However, it could be clearly seen from the SEM images that the pre-modification step prevents the formation of voids at the monolith-membrane pore interface. Larger specific surface area and pore volume values for composite membranes, prepared after pre-modification, fully support the SEM results. Especially large differences in pore structure between the two different composite membranes were found in the mesopore range. The results of this study indicate that it is possible to prepare porous, composite membranes where the trans-membrane transport is exclusively controlled by the pore and surface structure of a functional polymeric monolith, for example, made from a molecularly-imprinted polymer. [source] Synthesis of Large-Area Three-Dimensional Polyaniline Nanowire Networks Using a "Soft Template"MACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2005Wenbin Zhong Abstract Summary: Three-dimensional polyaniline (PANI) nanowire networks were synthesized in high yield using a "soft template" self-assembled with hexadecyltrimethylammonium bromide and oxalic acid. The PANI nanowire networks had diameters from 35,100 nm depending on synthesis conditions and/or procedures. The networks and the "cross-linking points" were clearly observed by field-emission scanning electron microscopy and transmission electron microscopy. A possible mechanism for the formation of three-dimensional PANI nanowire networks is discussed. FESEM image of PANI with three-dimensional nanowire networks. [source] Microreactor Array Assembly, Designed for Diversity Oriented Synthesis Using a Multiple Core Structure Library on Solid SupportMOLECULAR INFORMATICS, Issue 11 2006Alexander Groß Abstract The application of spatially encoded principles in solid phase combinatorial synthesis requires no chemical or physical coding strategies. The resulting products are encoded by their position inside the array and their synthesis history. The advantages of microreactor arrays for solid phase synthesis as one of the embodiments in the field of microreaction technology are discussed. Here, we review the reactor design, necessary process steps, and a strategy for the diversity oriented array synthesis. In particular, the glass-made microreactor and its assembly for 1563 parallel solid phase reactions, which can be performed at temperatures up to 120,°C, are described. Bead loading and liquid handling steps were adapted to this array. The production of large libraries demands suitable synthesis protocols and building blocks. The optimization of appropriate synthesis conditions is a time-consuming process. A multiple core structure library approach for the efficient synthesis of diverse heterocyclic libraries is described. The aim of this work was to prove the feasibility of the glass-microreaction array for massive parallel library synthesis. [source] Effects of synthesis conditions on crystal morphological structures and thermal degradation behavior of hydrotalcites and flame retardant and mechanical properties of EVA/hydrotalcite blendsPOLYMER COMPOSITES, Issue 2 2007Longchao Du The effects of synthesis methods and reaction conditions on the crystal morphological structures and thermal degradation behavior of hydrotalcites have been studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), particle size analysis (PSA), and differential thermal analysis (DTA). The flame retardant and mechanical properties of ethylene,vinyl acetate (EVA) blends with the corresponding hydrotalcites have been estimated by limiting oxygen index (LOI), UL-94, and mechanical measurements. The results from the XRD, TEM, and PSA demonstrate that the hydrotalcites synthesized by ultrasound method have larger crystal sizes and particle size distribution than those by mechanical stirring method. Higher reaction temperature, longer dripping time, and lower solution concentration can increase the crystal and particle sizes of ultrasound-synthesized hydrotalcites, whereas the longer ultrasound aging time can increase the crystal sizes and decrease the particle sizes of hydrotalcites because of the smashing conglomeration. The DTA data give a positive evidence that the hydrotalcite samples prepared by mechanical stirring method with longer alkaline dripping time have higher thermal degradation temperature than those by ultrasound method, since the ultrasound-synthesized hydrotalcites have more lattice defects than stirring-prepared hydrotalcites. The data from LOI, UL-94, and mechanical tests show that the ultrasonic-synthesized hydrotalcites have better flame retardant properties, whereas the stirring-synthesized hydrotalcites have better tensile strength in the EVA/hydrotalcite blends. POLYM. COMPOS., 28:131,138, 2007. © 2007 Society of Plastics Engineers [source] Evaluation of the interfacial state in high impact polystyrene through dynamic mechanical analysis as a function of the synthesis conditions,POLYMER ENGINEERING & SCIENCE, Issue 11 2007R. Díaz de León High impact polystyrene was synthesized using two series of styrene/butadiene (SB) tapered block copolymers with a polystyrene (PS)/polybutadiene (PB) composition of 30/70 and 10/90 wt%. During the synthesis, concentration of initiator, SB and transfer agent were varied. From dynamic mechanical analysis, the corresponding , relaxation of the rubber phase was detected at low temperature (near ,100°C) and that of the glassy PS phase at high temperature (near 100°C). Also, another relaxation at temperature near 40°C was identified, which was associated to the , relaxation of the glassy PS phase. The variations found in the , relaxation of the rubber phase, were attributed to changes in the morphological structure as a consequence of variation in initiator, SB or transfer agent concentrations and in SB composition. , relaxation showed a strong dependency with the interfacial state between the rubber and the glassy phase, where an increase in the amount of graft PS at the interface, which promotes the interfacial adhesion between phases, causes an increase in the magnitude of , relaxation of the PS phase. The results were attributed to variations in the interfacial area as a result of the change in the particle size and to the contribution of molecular chains of each phase in participating in the relaxation process. POLYM. ENG. SCI., 47:1827,1838, 2007. © 2007 Society of Plastics Engineers [source] Reaction kinetics of graft copolymerization and thermochemical studies of the degradation of poly(vinyl alcohol) graft copolymerPOLYMER INTERNATIONAL, Issue 3 2001Yassin A Aggour Abstract Poly(vinyl alcohol) (PVA) is a water-soluble and biomedical polymer. 2-Acrylamido-2-methyl-1-propanesulfonic acid was grafted onto PVA using ammonium persulfate as radical initiator. The influences of synthesis conditions such as temperature, concentrations of initiator, PVA and monomer were investigated. Both the initial rate of grafting and the final percentage of grafting were increased by an increase in reaction temperature. The reaction kinetics were studied to determine the rate constants of the first-order reactions. An activation energy of 16.3,kJ,mol,1 was found for the grafting reaction. The graft copolymers were characterized by IR and intrinsic viscosity measurements. A proposed mechanism of the grafting reaction is discussed. Kinetics of the thermal degradation were studied using a thermogravimetric method and the order of thermal stabilities are given. The apparent activation thermodynamic parameters, Ea, ,H*, ,S* and ,G* were determined and correlated to the thermal stabilities of the homo- and grafted polymers. © 2001 Society of Chemical Industry [source] Correlating the surface area and synthesis conditions of block co-polymer templated mesoporous silicaASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010A. T. Harris Abstract In this work we investigate the influence of (1) temperature, (2) curing (post reaction ageing) technique, (3) curing time, (4) surfactant (block co-polymer) concentration, and (5) the addition of secondary (pore swelling) reagents on the surface area and structure of ordered hexagonal mesoporous silica (SBA-15). We also investigate the use of microwave preparation and curing techniques, as a precursor to the development of large-scale synthesis processes for mesoporous silica. Samples were analyzed using transmission electron microscopy and nitrogen pore size analysis. The results of the study show that it is possible to optimize the surface area of the final material in a reproducible way, by using higher hydrolysis temperatures or lower surfactant concentrations. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Ion-Exchange Plasma Membranes for Fuel Cells on a Micrometer Scale,CHEMICAL VAPOR DEPOSITION, Issue 6-7 2007S. Roualdès Abstract Recent advances in,miniaturization technology make polymer electrolyte membrane fuel cells very attractive as power sources for portable devices. Ion-exchange membranes for microscale fuel cells are synthesized by plasma polymerization (using a precursor containing ion-exchange groups) and intensively characterized. Ion-exchange plasma membranes are thin, amorphous, and dense materials with no defects. Spectroscopic analyses reveal a polymer-type matrix containing a rather high concentration of ion-exchange groups. Under the best synthesis conditions, membranes show a satisfying ionic conduction level and a high compatibility with other active layers of fuel cells, making them suitable for insertion in such power-supply devices. [source] Gadolinium-Based Mixed-Metal Nitride Clusterfullerenes GdxSc3,xN@C80 (x=1, 2),CHEMPHYSCHEM, Issue 9 2006Shangfeng Yang Dr. Abstract The first gadolinium-based mixed-metal nitride clusterfullerenes GdxSc3,xN@C80 (I) (1, x=2; 2, x=1) have been successfully synthesized by the reactive gas atmosphere method and isolated facilely by recycling high-performance liquid chromatography (HPLC). The sum yield of 1 and 2 is 30,40 times higher than that of Gd3N@C80 (I). Moreover, an enhanced relative yield of 2 over the Sc3N@C80 (I) is achieved under the optimized synthesis conditions. According to the UV/Vis/NIR spectroscopic characterization, 1 and 2 are both stable fullerenes with large optical band-gaps while 1 has higher similarity to Gd3N@C80 (I) and 2 resembles Sc3N@C80 (I). The vibrational structures of 1 and 2 are studied by Fourier-transform infrared (FTIR) spectroscopy as well as density functional theory (DFT) computations. In particular, the structures of the encaged GdxSc3,xN clusters within 1 and 2 are analyzed. [source] | |||||||||||||||||||||||||