bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Direct Heat Measurement of Mechanical Energy Storage Metal–Organic Frameworks
Authors: Rodriguez Julien , Beurroies Isabelle , Loiseau Thierry , Denoyel Renaud , Llewellyn Philip L. 
Published: February 2015

AbstractIn any process, the heat exchanged is an essential property required in its development. Whilst the work related to structural transitions of some flexible metal–organic frameworks (MOFs) has been quantified and linked with potential applications such as molecular springs or shock absorbers, the heat related to such transitions has never been directly measured. This has now been carried out with MIL‐53(Al) using specifically devised calorimetry experiments. We project the importance of these heats in devices such as molecular springs or dampers.
Totalsynthese und biologische Evaluierung von Miuraenamiden
Authors: Karmann Lisa , Schultz Katharina , Herrmann Jennifer , Müller Rolf , Kazmaier Uli 
Published: February 2015

AbstractMiuraenamide, vergleichsweise einfache Vertreter einer Klasse von Cyclodepsipeptiden mit hoher Antitumor‐Aktivität, lassen sich nach dem Konzept der Peptidmodifizierung schnell und flexibel aufbauen. Die Einführung der ungewöhnlichen α,β‐Dehydroaminosäure gelingt durch Aldolreaktion/Oxidation an einem Glycin‐haltigen Cyclodepsipeptid in einer der letzten Stufen der Synthese.
Flow‐Enabled Self‐Assembly of Large‐Scale Aligned Nanowires
Authors: Li Bo , Zhang Chuchu , Jiang Beibei , Han Wei , Lin Zhiqun 
Published: February 2015

AbstractOne‐dimensional nanowires enable the realization of optical and electronic nanodevices that may find applications in energy conversion and storage systems. Herein, large‐scale aligned DNA nanowires were crafted by flow‐enabled self‐assembly (FESA). The highly oriented and continuous DNA nanowires were then capitalized on either as a template to form metallic nanowires by exposing DNA nanowires that had been preloaded with metal salts to an oxygen plasma or as a scaffold to direct the positioning and alignment of metal nanoparticles and nanorods. The FESA strategy is simple and easy to implement and thus a promising new method for the low‐cost synthesis of large‐scale one‐dimensional nanostructures for nanodevices.
Cyclopropene Derivatives as Precursors to Enantioenriched Cyclopropanols and n‐Butenals Possessing Quaternary Carbon Stereocenters
Authors: Simaan Marwan , Delaye Pierre‐Olivier , Shi Min , Marek Ilan 
Published: February 2015

AbstractThe diastereoselective carbocupration reaction of cyclopropenylmethyl ethers followed by addition of oxenoid leads to the formation of diastereo‐ and enantiomerically enriched 2,2,3,3‐tetrasubstituted cyclopropanol derivatives. Ring fragmentation of the copper cyclopropanolate leads to acyclic butenal derivatives possessing enantiomerically enriched α‐quaternary carbon stereocenters in a single‐pot operation.
Catalytic Asymmetric Diels–Alder Reaction of Quinone Imine Ketals: A Site‐Divergent Approach
Authors: Hashimoto Takuya , Nakatsu Hiroki , Maruoka Keiji 
Published: February 2015

AbstractThe catalytic asymmetric Diels–Alder reaction of quinone imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl‐substituted quinone derivatives which have not been applied in previous asymmetric quinone Diels–Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3‐alkyl quinone imine ketals from the inherently favored unsubstituted CC bond to the disfavored alkyl‐substituted CC bond.
Divinyl‐End‐Functionalized Polyethylenes: Ready Access to a Range of Telechelic Polyethylenes through Thiol–Ene Reactions
Authors: Norsic Sebastien , Thomas Coralie , D'Agosto Franck , Boisson Christophe 
Published: February 2015

AbstractTelechelic α,ω‐iodo‐vinyl‐polyethylenes (Vin‐PE‐I) were obtained by catalytic ethylene polymerization in the presence of [(C5Me5)2NdCl2Li(OEt2)2] in combination with a functionalized chain‐transfer agent, namely, di(10‐undecenyl)magnesium, followed by treatment of the resulting di(vinylpolyethylenyl)magnesium compounds ((vinyl‐PE)2Mg) with I2. The iodo‐functionalized vinylpolyethylenes (Vin‐PE‐I) were transformed into unique divinyl‐functionalized polyethylenes (Vin‐PE‐Vin) by simple treatment with tBuOK in toluene at 95 °C. Thiol–ene reactions were then successfully performed on Vin‐PE‐Vin with functionalized thiols in the presence of AIBN. A range of homobifunctional telechelic polyethylenes were obtained on which a hydroxy, diol, carboxylic acid, amine, ammonium chloride, trimethoxysilyl, chloro, or fluoroalkyl group was installed quantitatively at each chain end.
An Unusual Terpene Cyclization Mechanism Involving a Carbon–Carbon Bond Rearrangement
Authors: Meguro Ayuko , Motoyoshi Yudai , Teramoto Kazuya , Ueda Shota , Totsuka Yusuke , Ando Yumi , Tomita Takeo , Kim Seung‐Young , Kimura Tomoyuki , Igarashi Masayuki , Sawa Ryuichi , Shinada Tetsuro , Nishiyama Makoto , Kuzuyama Tomohisa 
Published: February 2015

AbstractTerpene cyclization reactions are fascinating owing to the precise control of connectivity and stereochemistry during the catalytic process. Cyclooctat‐9‐en‐7‐ol synthase (CotB2) synthesizes an unusual 5‐8‐5 fused‐ring structure with six chiral centers from the universal diterpene precursor, the achiral C20 geranylgeranyl diphosphate substrate. An unusual new mechanism for the exquisite CotB2‐catalyzed cyclization that involves a carbon–carbon backbone rearrangement and three long‐range hydride shifts is proposed, based on a powerful combination of in vivo studies using uniformly 13C‐labeled glucose and in vitro reactions of regiospecifically deuterium‐substituted geranylgeranyl diphosphate substrates. This study shows that CotB2 elegantly demonstrates the synthetic virtuosity and stereochemical control that evolution has conferred on terpene synthases.
Dissolution and utilization of chitosan in a 1‐carboxymethyl‐3‐methylimidazolium hydrochloride ionic salt aqueous solution
Authors: Feng Jiaxuan , Zang Hongjun , Yan Qing , Li Mingguang , Jiang Xinqiang , Cheng Bowen 
Published: February 2015

ABSTRACT1‐Carboxymethyl‐3‐methylimidazolium hydrochloride ([IMIM–COOH]Cl), a new ionic salt, is proposed as a green, promising solvent for dissolving chitosan. However, because of the optimal dosage of chitosan dissolved in [IMIM–COOH]Cl, a 12 wt % [IMIM–COOH]Cl aqueous solution was selected as an optimum solvent system for dissolving chitosan. The structures of the original and regenerated chitosan were characterized by Fourier transform infrared spectroscopy and X‐ray diffraction analysis. Scanning electron microscopy was used to visualize the morphological features of the reconstituted chitosan membranes. Meanwhile, the absorbance, tensile strength, and breaking elongation of the chitosan membranes were measured. The results reveal that 10–11 wt % was an optimal chitosan concentration for preparing membranes. Furthermore, the adsorption capacity for Cu(II) ion of the chitosan membranes was increased with the chitosan concentration decreased from 12 to 8 wt %. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41965.
Poly(styrene–maleic anhydride) functionalized graphene oxide
Authors: Zhou Longfei , Liu Haihui , Zhang Xingxiang 
Published: February 2015

ABSTRACTIn this study, poly(styrene–maleic anhydride) functionalized graphene oxide (SMAFG) was fabricated with in situ polymerization. The sample was characterized with Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and ultraviolet–visible absorption. The results of the experiments show that the thermal stability of SMAFG was improved significantly, and it also possessed a good dispersion in N,N‐dimethylformamide, N,N‐dimethylacetamide, aniline, and certain organic solvents. The calculated Hildebrand parameter of SMAFG was 23.8 MPa1/2. This new method will broaden the applications of graphene, and the experiment showed that it could effectively improve the strength of polyamide 6 (PA6) compared with the pure PA6 fiber. The tensile strength of the SMAFG/PA6 composite fiber improved 29%, and the Young's modulus improved 33%, so this kind of functionalized graphene oxide can be used in the preparation of polymeric composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41987.
Preparation of aluminum hydroxide/aluminum phosphinate flame‐retardant poly(vinyl alcohol) foam through thermal processing
Authors: Liu Pengju , Bai Shibing , Wang Qi 
Published: February 2015

ABSTRACTA novel flame‐retardant poly (vinyl alcohol) (PVA) composite foam was prepared successfully through thermal processing, which was filled with high content of flame retardant, based on aluminum hydroxide (ATH) and aluminum phosphinate (AlPi) and using water as plasticizer and blowing agent. The flame‐retardant property and mechanism of the prepared foam matrix were studied by vertical burning test, limiting oxygen index (LOI), cone calorimeter, scanning electronic microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The experimental results showed that the PVA/ATH/AlPi (1/1.2/0.05) composite achieved LOI value of 41% and UL94 V‐0 (3.2 mm) rate. The addition of ATH and AlPi into PVA matrix significantly decreased flammability of the composites, because a more compact and continuous char layer of the PVA/ATH/AlPi composite could be formed, due to the involvement of AlPi in the char‐forming reaction. Compared with the pure PVA sample, the peak heat release rate (PHRR) and total heat release (THR) of PVA/ATH/AlPi (1/1.2/0.05) composite were reduced by 76.5% and 58.2%, respectively. Built upon this PVA‐based foam matrix with good flame retardancy, the flame‐retardant PVA‐based foam was successfully prepared through thermal extrusion. In addition, the influence of water content on melt viscosity, foam structure and mechanical strength was also analyzed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42020.
Hyperelasticity, dynamic mechanical property, and rheology of addition‐type silicone rubber (VPDMS cured by PMHS)
Authors: Hao Dong , Li Dongxu , Liao Yihuan 
Published: February 2015

ABSTRACTThe aerospace‐level addition‐type silicone rubber (ASR) was prepared by vinyl‐terminated polydimethylsiloxane (VPDMS) and aerospace‐level polymethylhydrosiloxane (PMHS) and its mechanical properties were investigated through the hyperelastic measurements, the dynamic mechanical tests and the rheological experiments. The hyperelastic analysis shows that the tensile strength and the break strain are separately 3.00 MPa and 281%, and the proposed model exhibits good descriptions of the uniaxial behaviors. The dynamic mechanical analysis indicates that two transition temperatures are observed for the ASR. The storage modulus, the loss modulus and the loss factor become stable when the temperature is higher than −35°C. The rheological analysis presents that the storage and loss modulus appeared an obvious growth with increasing frequency at the temperature of −120 and −110°C. The moduli have an apparent nonlinear dependence on the strain amplitude and a nonlinear function is utilized to express that relationship. This nonlinear model shows well agreements with the experimental data. The investigations on the aerospace‐level ASR in this article have some meanings for its usage in aerospace products. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42036.
Induction therapy with cetuximab plus docetaxel, cisplatin, and 5‐fluorouracil (ETPF) in patients with resectable nonmetastatic stage III or IV squamous cell carcinoma of the oropharynx. A GERCOR phase II ECHO‐07 study
Authors: Chibaudel Benoist , Lacave Roger , Lefevre Marine , Soussan Patrick , Antoine Martine , Périé Sophie , Belloc Jean‐Baptiste , Banal Alain , Albert Sébastien , Chabolle Frédéric , Céruse Philippe , Baril Philippe , Gatineau Michel , Housset Martin , Moukoko Rachel , Benetkiewicz Magdalena , de Gramont Aimery , Bonnetain Franck , Lacau St Guily Jean 
Published: February 2015

AbstractInduction TPF regimen is a standard treatment option for squamous cell carcinoma (SCC) of the oropharynx. The efficacy and safety of adding cetuximab to induction TPF (ETPF) therapy was evaluated. Patients with nonmetastatic resectable stage III/IV SCC of the oropharynx were treated with weekly cetuximab followed the same day by docetaxel and cisplatin and by a continuous infusion of 5‐fluorouracil on days 1‐5 (every 3 weeks, 3 cycles). The primary endpoint was clinical and radiological complete response (crCR) of primary tumor at 3 months. Secondary endpoints were crCR rates, overall response, pathological CR, progression‐free survival, overall survival, and safety. Forty‐two patients were enrolled, and 41 received ETPF. The all nine planned cetuximab doses and the full three doses of planned chemotherapy were completed in 31 (76%) and 36 (88%) patients, respectively. Twelve (29%) patients required dose reduction. The crCR of primary tumor at the completion of therapy was observed in nine (22%) patients. ETPF was associated with a tumor objective response rate (ORR) of 58%. The most frequent grade 3–4 toxicities were as follows: nonfebrile neutropenia (39%), febrile neutropenia (19%), diarrhea (10%), and stomatitis (12%). Eighteen (44%) patients experienced acne‐like skin reactions of any grade. One toxic death occurred secondary to chemotherapy‐induced colitis with colonic perforation. This phase II study reports an interesting response rate for ETPF in patients with moderately advanced SCC of the oropharynx. The schedule of ETPF evaluated in this study cannot be recommended at this dosage.
Alternative Reagents for Methotrexate as Immobilizing Anchor Moieties in the Optimization of MASPIT: Synthesis and Biological Evaluation
Authors: De Clercq Dries J. H. , Risseeuw Martijn D. P. , Karalic Izet , De Smet Anne‐Sophie , Defever Dieter , Tavernier Jan , Lievens Sam , Van Calenbergh Serge 
Published: February 2015

AbstractWe report the evaluation of two alternative chemical dimerizer approaches aimed at increasing the sensitivity of MASPIT, a three‐hybrid system that enables small‐molecule target protein profiling in intact human cells. To circumvent the potential limitations related to the binding of methotrexate (MTX) to endogenous human dihydrofolate reductase (DHFR), we explored trimethoprim (TMP) as an alternative prokaryote‐specific DHFR ligand. MASPIT evaluation of TMP fusion compounds with tamoxifen, reversine, and simvastatin as model baits, resulted in dose–response curves shifted towards lower EC50 values than those of their MTX congeners. Furthermore, a scalable azido‐TMP reagent was synthesized that displayed a similar improvement in sensitivity, possibly owing to increased membrane permeability relative to the MTX anchor. Applying the SNAP‐tag approach to introduce a covalent bond into the system, on the other hand, produced an inferior readout than in the MTX‐ or TMP‐tag based assay.
Pyrochlore and Perovskite Potassium Tantalate: Enthalpies of Formation and Phase Transformation
Authors: Zlotnik Sebastian , Sahu Sulata K. , Navrotsky Alexandra , Vilarinho Paula M. 
Published: February 2015

AbstractAlkali niobates and tantalates are currently important lead‐free functional oxides. The formation and decomposition energetics of potassium tantalum oxide compounds (K2OTa2O5) were measured by high‐temperature oxide melt solution calorimetry. The enthalpies of formation from oxides of KTaO3 perovskite and defect pyrochlores with K/Ta ratio of less than 1 stoichiometry—K0.873Ta2.226O6, K1.128Ta2.175O6, and K1.291Ta2.142O6—were experimentally determined, and the values are (−203.63±2.92) kJ mol−1 for KTaO3 perovskite, and (−339.54±5.03) kJ mol−1, (−369.71±4.84) kJ mol−1, and (−364.78±4.24) kJ mol−1, respectively, for non‐stoichiometric pyrochlores. That of stoichiometric defect K2Ta2O6 pyrochlore, by extrapolation, is (−409.87±6.89) kJ mol−1. Thus, the enthalpy of the stoichiometric pyrochlore and perovskite at K/Ta=1 stoichiometry are equal in energy within experimental error. By providing data on the thermodynamic stability of each phase, this work supplies knowledge on the phase‐formation process and phase stability within the K2OTa2O5 system, thus assisting in the synthesis of materials with reproducible properties based on controlled processing. Additionally, the relation of stoichiometric and non‐stoichiometric pyrochlore with perovskite structure in potassium tantalum oxide system is discussed.
Chiral Perylene Diimides: Building Blocks for Ionic Self‐Assembly
Authors: Echue Geraldine , Lloyd‐Jones Guy C. , Faul Charl F. J. 
Published: February 2015

AbstractA chiral perylene diimide building block has been prepared based on an amine derivative of the amino acid L‐phenylalanine. Detailed studies were carried out into the self‐assembly behaviour of the material in solution and the solid state using UV/Vis, circular dichroism (CD) and fluorescence spectroscopy. For the charged building block BTPPP, the molecular chirality of the side chains is translated into the chiral supramolecular structure in the form of right‐handed helical aggregates in aqueous solution. Temperature‐dependent UV/Vis studies of BTPPP in aqueous solution showed that the self‐assembly behaviour of this dye can be well described by an isodesmic model in which aggregation occurs to generate short stacks in a reversible manner. Wide‐angle X‐ray diffraction studies (WXRD) revealed that this material self‐organises into aggregates with π–π stacking distances typical for π‐conjugated materials. TEM investigations revealed the formation of self‐assembled structures of low order and with no expression of chirality evident. Differential scanning calorimetry (DSC) and polarised optical microscopy (POM) were used to investigate the mesophase properties. Optical textures representative of columnar liquid–crystalline phases were observed for solvent‐annealed samples of BTPPP. The high solubility, tunable self‐assembly and chiral ordering of these materials demonstrate their potential as new molecular building blocks for use in the construction of chiro‐optical structures and devices.
Selective Ruthenium Labeling of the Tryptophan Residue in the Bee Venom Peptide Melittin
Authors: Perekalin Dmitry S. , Novikov Valentin V. , Pavlov Alexander A. , Ivanov Igor A. , Anisimova Natalia Yu. , Kopylov Alexey N. , Volkov Dmitry S. , Seregina Irina F. , Bolshov Michail A. , Kudinov Alexander R. 
Published: February 2015

AbstractMelittin is a membrane‐active peptide from bee venom with promising antimicrobial and anticancer activity. Herein we report on a simple and selective method for labeling of the tryptophan residue in melittin by the organometallic fragment [(C5H5)Ru]+ in aqueous solution and in air. Ruthenium coordination does not disturb the secondary structure of the peptide (as verified by 2D NMR spectroscopy), but changes the pattern of its intermolecular interactions resulting in an 11‐fold decrease of hemolytic activity. The high stability of the organometallic conjugate allowed the establishment of the biodistribution of the labeled melittin in mice by inductively coupled plasma MS analysis of ruthenium.
Calcium‐Catalyzed Formal [2+2+2] Cycloaddition
Authors: Meyer Vera J. , Ascheberg Christoph , Niggemann Meike 
Published: February 2015

AbstractA formal intermolecular [2+2+2] cycloaddition reaction of enynes to aldehydes is presented, which can be realized in the presence of a simple and benign calcium catalyst. The reaction proceeds with excellent chemo, regio‐ and diastereoselectivity and leads to a one‐step assembly of highly interesting bicyclic building blocks containing up to three stereocenters from simple precursors via a new type of skeletal rearrangement of enynes. The observed diastereoselectivity is accounted for by two different mechanistic proposals. The first one engages mechanistic prospects arising from a gold catalyzed reaction in the absence of the stabilizing gold substituent. The second proposal involves an unprecedented cyclization–carbonyl allene ene reaction–hydroalkoxylation cascade.
ChemInform Abstract: The 3R Polymorph of CaSi2.
Authors: Nedumkandathil Reji , Benson Daryn E. , Grins Jekabs , Spektor Kristina , Haeussermann Ulrich 
Published: February 2015

AbstractCaSi2 is prepared by arc melting the elements in the ratio Ca:Si = 1:2.02.
ChemInform Abstract: Magnetic Order and Crystal Structure Study of YNi4Si‐Type NdNi4Si.
Authors: Yao Jinlei , Isnard O. , Morozkin A. V. , Ivanova T. I. , Koshkido'ko Yu. S. , Bogdanov A. E. , Nikitin S. A. , Suski W. 
Published: February 2015

AbstractNdNi4Si is prepared by arc melting of stoichiometric amounts of the elements followed by annealing under Ar (quartz tube, 1070 K, 200 h).
ChemInform Abstract: Synthesis, Crystal Structure and Ion Mobility in the Complex Fluorides of Antimony (III) with the Lithium Cation.
Authors: Makarenko N. V. , Udovenko A. A. , Zemnukhova L. A. , Kavun V. Ya. , Polyantsev M. M. 
Published: February 2015

AbstractCompounds (III) and (IV) are characterized by single crystal XRD, IR, 7Li, and 19F NMR spectroscopy.
ChemInform Abstract: Ba2TeO: A New Layered Oxytelluride.
Authors: Besara T. , Ramirez D. , Sun J. , Whalen J. B. , Tokumoto T. D. , McGill S. A. , Singh D. J. , Siegrist T. 
Published: February 2015

AbstractSingle crystals of the semiconducting Ba2TeO are prepared from BaO and Te in a molten Ba flux in the molar ratio of 1:1:20 (steel crucible in evacuated quartz tube, 1000 °C, 20 h; cooling to 820 °C within 50 h).
ChemInform Abstract: Bismuth Zinc Vanadate, BiZn2VO6: New Crystal Structure Type and Electronic Structure.
Authors: Eliziario Nunes Sayonara , Wang Chun‐Hai , So Karwei , Evans John S. O. , Radosavljevic Evans Ivana 
Published: February 2015

AbstractBiZn2VO6 is prepared by firing stoichiometric amounts of Bi2O3, ZnO, CuO, and NH4VO3 (Al2O3 crucible, 1.
ChemInform Abstract: Ca2Cr0.5Ga1.5O5 — An Extremely Redox‐Stable Brownmillerite Phase.
Authors: Luo Kun , Amano Patino Midori , Hayward Michael A. 
Published: February 2015

AbstractSamples of Ca2CrxGa2‐xO5 are prepared by solid state reaction of stoichiometric amounts of CaCO3, Ga2O3, and Cr2O3 under Ar (1.
ChemInform Abstract: Controlling the Ring Curvature, Solution Assembly, and Reactivity of Gigantic Molybdenum Blue Wheels.
Authors: Xuan Weimin , Surman Andrew J. , Miras Haralampos N. , Long De‐Liang , Cronin Leroy 
Published: February 2015

AbstractCompounds (III) and (IV) are synthesized by reduction of an acidified suspension of cerium polymolybdate in water and characterized by single crystal XRD, IR and Raman spectroscopy, and electrospray‐ionization ion‐mobility mass spectrometry.
ChemInform Abstract: Synthesis, Structure and Properties of Layered Iron‐Oxychalcogenides Nd2Fe2Se2‐xSxO3.
Authors: Liu Y. , Zhang S. B. , Tan S. G. , Yuan B. , Kan X. C. , Zu L. , Sun Y. P. 
Published: February 2015

AbstractThe new series of title compounds (x = 0, 0.1, 0.2, 0.3, 0.4) is synthesized by solid state reaction of stoichiometric mixtures of Nd2O3, Fe, Se, and S powders (evacuated quartz tubes, 1273 K, 48 h).
ChemInform Abstract: Four High‐Temperature Ferromagnets in the Hf—Fe—Sn System.
Authors: Calta Nicholas P. , Francisco Melanie C. , Malliakas Christos D. , Schlueter John A. , Kanatzidis Mercouri G. 
Published: February 2015

AbstractHf1.823Fe5Sn3.815 (I), HfFe2‐xSnx (II), and two polymorphs of Hf1‐xFe2Snx (III), all closely related to HfFe2 Laves phase parent structures are prepared by melting the elements using excess Sn as a flux (Al crucible in evacuated silica tube, 1100 °C within 17 h; cooling to 600 (I) and 850 °C (II) and (III) within 50 h for Sn removal by centrifugation) prior to HCl etching of residual Sn and magnetic separation.
ChemInform Abstract: Synthesis, Crystal Structure and Electrical Proprieties of New Phosphate KCoP3O9.
Authors: Ben Smida Y. , Guesmi A. , Georges S. , Zid M. F. 
Published: February 2015

AbstractCrystals of the new title compound are prepared by solid state reaction of K2CO3, Co(OAc)2·4H2O, and NH4H2PO4 in the molar ratio of K:Co:P = 1:1:3 (porcelain crucible, 300 °C in air for 12 h and 820 °C for 3 d).