共查询到20条相似文献,搜索用时 31 毫秒
1.
以聚硅碳硅烷(PSCS)与乙酰丙酮铝(Al(AcAc)3)为原料,在常压高温条件下反应制备出聚铝碳硅烷(PACS),经过熔融纺丝制备了PACS纤维.应用GPC、IR、XPS、29Si-NMR、27Al-NMR、TG、SEM、元素分析和增重等一系列分析,分别对PACS纤维的微观组成、结构以及性能进行了分析.研究结果表明,以原料质量配比为6∶100(Al(AcAc)3∶PSCS)合成的PACS化学式为SiC2.0H7.5O0.13Al0.018,数均分子量为1700左右,最适宜制备PACS纤维;PACS纤维中主要存在SiC4、SiC3H等结构,同时存在Si—O—Al键;在氮气气氛中,PACS纤维的陶瓷产率达到52%左右;预氧化处理,PACS纤维中Si—H键与空气中的氧反应形成Si—O—Si交联结构,较聚碳硅烷(PCS)纤维易于氧化,经过预氧化的PACS纤维陶瓷产率达到80%左右,是制备耐超高温SiC(Al)陶瓷纤维的合适纤维;用预氧化PACS纤维制备的SiC(OAl)纤维和SiC(Al)纤维抗拉强度高,耐高温性能好. 相似文献
2.
采用不同比例的乙酰丙酮铝[Al(AcAc)3]与聚硅碳硅烷(PSCS)反应制备含铝碳化硅陶瓷的先驱体聚铝碳硅烷(PACS). 采用气相凝胶色谱(GPC)、化学分析和红外等手段对不同铝含量的PACS组成和结构进行了表征, 研究了铝含量对PACS结构和性能的影响. 结果表明, 随着铝含量的增加, PACS的氧含量增加, 分子量分布变宽, 主要活性基团Si—H键的含量降低, PACS的可纺性降低. 当Al(AcAc)3/PSCS(质量比)大于20%以后, PACS不可纺. 热重-差热分析(TG-DTA)的研究表明: 当制备PACS的Al(AcAc)3/PSCS(质量比)大于4%, PACS在N2中400~560 ℃之间的失重明显降低. 铝含量在0.4~0.7 wt%的PACS, 制备的Si-Al-C-O纤维抗张强度最高. Al(AcAc)3/PSCS=6 wt%时制备的PACS, 烧结的SiC(Al)纤维最致密. 相似文献
3.
Six‐coordinated vanadium(IV) complexes with tridentate task‐specific ionic liquid Schiff base ligands: Synthesis,characterization and effect of ionic nature on catalytic activity
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
By reaction of 5‐(chloromethyl)salicylaldehyde with triphenylphosphine and N‐methylimidazole in two separate reactions, salicylaldehydetriphenylphosphonium chloride (S2) and salicylaldehydemethylimidazolinium chloride (S3) were prepared. Reaction of 2‐(aminomethyl)pyridine with these aldehydes resulted in the task‐specific ionic liquid Schiff base ligands L1 and L2, respectively. Then six‐coordinated vanadium(IV) Schiff base complexes of VO(acac)L1–4 were synthesized by reactions of these tridentate Schiff base ligands and VO(acac)2 in 1:1 stoichiometry. The aldehydes, ligands and VO(acac)L1–4 complexes were characterized using infrared, 1H NMR, 13C NMR, 31P NMR, UV–visible and mass spectroscopies, as well as elemental analysis. Paramagnetic property of the complexes was also studied using magnetic susceptibility measurements. The complexes were used as catalysts in epoxidation of cyclooctene and oxidation of methylphenyl sulfide and the reaction parameters were optimized. The effect of the ionic nature of the complexes was investigated in these oxidation reactions. The catalytic activity of the complexes could be varied by changing the ionic (cationic or anionic) character of VO(acac)L1–4 catalysts in which counter anion variation showed a greater effect than cationic moiety variation. 相似文献
4.
Kiyoshi Endo Naoyoshi Hatakeyama 《Journal of polymer science. Part A, Polymer chemistry》2001,39(16):2793-2798
The polymerization of butadiene (Bd) with Co(acac)3 in combination with methylaluminoxane (MAO) was investigated. The polymerization of Bd with Co(acac)3‐MAO catalysts proceeded to give cis‐1,4 polymers (94 – 97%) bearing high molecular weights (40 × 104) with relatively narrow molecular weight distributions (Mw's/Mn's). The molecular weight of the polymers increased linearly with the polymer yield, and the line passed through an original point. The polydispersities of the polymers kept almost constant during reaction time. This indicates that the microstructure and molecular weight of the polymers can be controlled in the polymerization of Bd with the Co(acac)3‐MAO catalyst. The effects of reaction temperature, Bd concentration, and the MAO/Co molar ratio on the cis‐1,4 microstructure and high molecular weight polymer in the polymerization of Bd with Co(acac)3‐MAO catalyst were observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2793–2798, 2001 相似文献
5.
Jan Svoboda Jan Sedláček Jiří Zedník Gita Dvořáková Olga Trhlíková Dana Rédrová Hynek Balcar Jiří Vohlídal 《Journal of polymer science. Part A, Polymer chemistry》2008,46(8):2776-2787
3‐Ethynylthiophene (3ETh) was polymerized with Rh(I) complexes: [Rh(cod)acac], [Rh(nbd)acac], [Rh(cod)Cl]2, and [Rh(nbd)Cl]2 (cod is η2:η2‐cycloocta‐1,5‐diene and nbd η2:η2‐norborna‐2,5‐diene), used as homogeneous catalysts and with the last two complexes anchored on mesoporous polybenzimidazole (PBI) beads: [Rh(cod)Cl]2/PBI and [Rh(nbd)Cl]2/PBI used as heterogeneous catalysts. All tested catalyst systems give high‐cis poly(3ETh). In situ NMR study of homogeneous polymerizations induced with [Rh(cod)acac] and [Rh(nbd)acac] complexes has revealed: (i) a transformation of acac ligands into free acetylacetone (Hacac) occurring since the early stage of polymerization, which suggests that this reaction is part of the initiation, (ii) that the initiation is rather slow in both of these polymerization systems, and (iii) a release of cod ligand from [Rh(cod)acac] complex but no release of nbd ligand from [Rh(nbd)acac] complex during the polymerization. The stability of diene ligand binding to Rh‐atom in [Rh(diene)acac] catalysts remarkably affects only the molecular weight but not the yield of poly(3ETh). The heterogeneous catalyst systems also provide high‐cis poly(3ETh), which is of very low contamination with catalyst residues since a leaching of anchored Rh complexes is negligible. The course of heterogeneous polymerizations is somewhat affected by limitations arising from the diffusion of monomer inside catalyst beads. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2776–2787, 2008 相似文献
6.
Jun Wang Na Zhang Weiguang Shi Yiteng Shang 《Journal of Coordination Chemistry》2017,70(15):2708-2721
Two hyperbranched bisphosphinoamine (PNP) ligands and chromium complexes were synthesized in good yield with 1.0 generation (1.0 G) hyperbranched macromolecules, chlorodiphenylphosphine (Ph2PCl) and CrCl3(THF)3 as raw materials. The hyperbranched PNP ligands and chromium complexes were characterized by FT-IR, 1H NMR, 31P NMR, UV and ESI-MS. Comparing with the chromium complexes, the hyperbranched PNP ligands, in combination with Cr(III), and activation by methylaluminoxane (MAO) in situ generated species with better catalytic performance for ethylene oligomerization. The effect of solvent, chromium source, ligand/Cr molar ratio, reaction temperature, Al/Cr molar ratio and reaction pressure on the catalytic activity and product selectivity were studied. The results showed that with increase of ligand/Cr molar ratio, reaction temperature and Al/Cr molar ratio, the catalytic activity increased at first and then decreased. However, the catalytic activity continuously increased with increase of reaction pressure. Under the optimized conditions, the catalytic system of hyperbranched PNP/Cr(III)/MAO led to catalytic activity of 2.68 × 105 g/(mol Cr·h) and 37.71% selectivity for C6 and C8. 相似文献
7.
Polymerization of n‐octylallene was successfully carried out using a conventional binary rare earth catalytic system composed of rare earth tris(2‐ethylhexylphosphonate) (Ln(P204)3) and tri‐isobutyl aluminum (Al(i‐Bu)3) for the first time. The effects of catalyst, solvent, reaction time and temperature on the polymerization of n‐octylallene were studied. The resulting poly(n‐octylallene) has weight‐average molecular weight of 11000, molecular weight distribution of 1.4 and 96% yield under the moderate reaction conditions: [Al]/[Y] =50 (molar ratio), [n‐octylallene]/[Y] =100 (molar ratio), polymerized at 80°C for 20 h in bulk. The poly(n‐octylallene) obtained consisted of 1,2‐ and 2,3‐polymerized units, and was characterized by FT‐IR, 1H NMR and GPC. Further investigation shows that the polymerization of n‐octylallene has some living polymerization characteristics, preparing the polymer with controlled molecular weight and narrower molecular weight distribution. 相似文献
8.
Trent R. Graham Jaehun Chun Gregory K. Schenter Xin Zhang Sue B. Clark Carolyn I. Pearce Kevin M. Rosso 《Magnetic resonance in chemistry : MRC》2022,60(2):226-238
Although nanometer-sized aluminum hydroxide clusters (i.e., ϵ-Al13, [Al13O4(OH)24(H2O)12]7+) command a central role in aluminum ion speciation and transformations between minerals, measurement of their translational diffusion is often limited to indirect methods. Here, 27Al pulsed field gradient stimulated echo nuclear magnetic resonance (PFGSTE NMR) spectroscopy has been applied to the AlO4 core of the ϵ-Al13 cluster with complementary theoretical simulations of the diffusion coefficient and corresponding hydrodynamic radii from a boundary element-based calculation. The tetrahedral AlO4 center of the ϵ-Al13 cluster is symmetric and exhibits only weak quadrupolar coupling, which results in favorable T1 and T2 27Al NMR relaxation coefficients for 27Al PFGSTE NMR studies. Stokes–Einstein relationship was used to relate the 27Al diffusion coefficient of the ϵ-Al13 cluster to the hydrodynamic radius for comparison with theoretical simulations, dynamic light scattering from literature, and previously published 1H PFGSTE NMR studies of chelated Keggin clusters. This first-of-its-kind observation proves that 27Al PFGSTE NMR diffusometry can probe symmetric Al environments in polynuclear clusters of greater molecular weight than previously considered. 相似文献
9.
Isao Ogino Bruce C. Gates Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(28):6827-6837
A set of supported ruthenium complexes with systematically varied ratios of chemisorbed to physisorbed species was formed by contacting cis‐[Ru(acac)2(C2H4)2] ( I ; acac=C5H7O2?) with dealuminated zeolite Y. Extended X‐ray absorption fine structure (EXAFS) spectra used to characterize the samples confirmed the systematic variation in the loadings of the two supported species and demonstrated that removal of bidentate acac ligands from I accompanied chemisorption to form [Ru(acac)(C2H4)2]+ attached through two Ru? O bonds to the Al sites of the zeolite. A high degree of uniformity in the chemisorbed species was demonstrated by sharp bands in the infrared (IR) spectrum characteristic of ruthenium dicarbonyls that formed when CO reacted with the anchored complex. When the ruthenium loading exceeded 1.0 wt % (Ru/Al≈1:6), the additional adsorbed species were simply physisorbed. Ethene ligands on the chemisorbed species reacted to form butenes when the temperature was raised to approximately 393 K; acac ligands remained bonded to Ru. In contrast, ethene ligands on the physisorbed complex simply desorbed under the same conditions. The chemisorption activated the ruthenium complex and facilitated dimerization of the ethene, which occurred catalytically. IR and EXAFS spectra of the supported samples indicate that 1) Ru centers in the chemisorbed species are more electron deficient than those in the physisorbed species and 2) Ru–ethene bonds in the chemisorbed species are less symmetric than those in the physisorbed species, which implies the presence of a preferred configuration for the catalytic dimerization. 相似文献
10.
A series of phosphorescent cyclometalated iridium complexes with 2,5‐diphenylpyridine‐based ligands has been synthesized and characterized to investigate the effect of the simple ligand modification on photophysics, thermostability and electrochemistry. The complexes have the general structure (C∧N)2Ir(acac), where C∧N is a monoanionic cyclometalating ligand [e.g. 2,5‐diphenylpyridyl (dppy), 2,5‐di(4‐methoxyphenyl)pyridyl (dmoppy), 2,5‐di(4‐ethoxyphenyl)pyridyl (deoppy) and 2,5‐di(4‐ethylphenyl)pyridyl (deppy)]. The absorption, emission, cyclic voltammetry and thermostability of the complexes were systematically investigated. The (dppy)2Ir(acac) has been characterized using X‐ray crystallography. Calculation on the electronic ground state of (dppy)2Ir(acac) was carried out using B3LYP density functional theory. The highest occupied molecular orbital (HOMO) level is a mixture of Ir and ligand orbitals, while the lowest occupied molecular orbital (LUMO) is predominantly dppy ligand‐based. Electrochemical studies showed the oxidation potentials of (dmoppy)2Ir(acac), (deoppy)2Ir(acac), (deppy)2Ir(acac) were smaller than that of (ppy)2Ir(acac), while the oxidation potential of (dppy)2Ir(acac) was larger relative to (ppy)2Ir(acac). The 10% weight reduction temperatures of these complexes were above that of (ppy)2Ir(acac). All complexes exhibited intense green photoluminescence, which has been attributed to MLCT triplet emission. The maximum emission wavelengths in CH2Cl2 at room temperature were in the range 531–544 nm, which is more red‐shifted than that of (ppy)2Ir(acac). Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
11.
Isao Ogino Mingyang Chen Jason Dyer Philip W. Kletnieks James F. Haw Prof. David A. Dixon Prof. Bruce C. Gates Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(25):7427-7436
An essentially molecular ruthenium–benzene complex anchored at the aluminum sites of dealuminated zeolite Y was formed by treating a zeolite‐supported mononuclear ruthenium complex, [Ru(acac)(η2‐C2H4)2]+ (acac=acetylacetonate, C5H7O2?), with 13C6H6 at 413 K. IR, 13C NMR, and extended X‐ray absorption fine structure (EXAFS) spectra of the sample reveal the replacement of two ethene ligands and one acac ligand in the original complex with one 13C6H6 ligand and the formation of adsorbed protonated acac (Hacac). The EXAFS results indicate that the supported [Ru(η6‐C6H6)]2+ incorporates an oxygen atom of the support to balance the charge, being bonded to the zeolite through three Ru? O bonds. The supported ruthenium–benzene complex is analogous to complexes with polyoxometalate ligands, consistent with the high structural uniformity of the zeolite‐supported species, which led to good agreement between the spectra and calculations at the density functional theory level. The calculations show that the interaction of the zeolite with the Hacac formed on treatment of the original complex with 13C6H6 drives the reaction to form the ruthenium–benzene complex. 相似文献
12.
Basic Aluminium Salts and their Solutions. XI. 27Al-NMR Studies Comparing the Mineral Zunyite and Basic Aluminium Salts of Tridecameric Al-oxo-hydroxo-aquo-Cations Solid-state high resolution 27Al NMR studies of basic aluminum sulphate and the mineral zunyite, both containing tridecameric Al-oxo-hydroxo groups, show different 27Al spectra. While for zunyite both AlO6 octahedra (0 ppm) and the central AlO4 tetrahedron (69 ppm) are observed in the spectrum, in the case of the basic aluminum sulphate only the tetrahedrally coordinated Al (59 ppm) is detected by NMR. This behaviour is explained by structural data, which indicate stronger distortions of the AlO6 octahedra in the case of the basic aluminum sulphate. The increased shielding of the fourcoordinated Al of the basic sulphate is attributed to an increased ionic character of the Al? O bond in this compound. 相似文献
13.
Syntheses and Structures of Acetyl‐Acetonato‐Alumo‐Diphenylsilanolates with Magnesium(II), Iron(II), Iron(III), Cobalt(II), and Nickel(II)
下载免费PDF全文
![点击此处可从《无机化学与普通化学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bis(acetylacetonate)alumo‐oxo‐tetraphenyldisiloxane‐metal(II) dihydrates [(acac)2Al(O–SiPh2–O–SiPh2–O)]2M(H2O)2 (M = Mg, Fe, Co, Ni) were obtained from the corresponding acetyl‐acetonate‐dihydrates (acac)2M(H2O)2 by reaction with the alumosiloxane [O–Ph2Si–O–SiPh2–O]4Al4(OH)4. These new compounds display two acac ligands at the aluminum atoms as well as disilatrioxy chains linking the two aluminum atoms forming a (Al–O–Si–O–Si–O)2 cycle (X‐ray structure analyses). Within this cycle the divalent metal ions M2+, to which two water molecules in trans positions are linked, are installed in almost planar MO4 coordination spheres. Using water free (acac)2Ni a different product forms: both reactants combine in a 2:1 ratio to yield [O–Ph2Si–O–SiPh2–O]4Al4(OH)2O(OH2)Ni2(acac)4. Here, three of the acac ligands were transposed to the aluminum atoms. The nickel atoms are in a distorted octahedral coordination mode from oxygen atoms of the ligands. When iron(III)tris(acetylacetonate) reacts with the alumosiloxane [O–Ph2Si–O–SiPh2–O]3Al2O(OH)Fe2(acac)3 was isolated, in which the two iron atoms still display one of the acac ligands. One of the aluminum atoms is in a tetrahedral oxygen environment, whereas the other is in the center of a trigonal bi‐pyramid formed of oxygen atoms either of the siloxane or of acac. The iron atoms have five‐ or sixfold coordination from oxygen atoms of siloxane, acac, hydroxide or oxide. 相似文献
14.
Xinli Zhang Zhi Liu Jianjun Yi Fengjiao Li Haibing Huang Wei Liu Hongpeng Zhen Qigu Huang Kejing Gao Wantai Yang 《Journal of polymer science. Part A, Polymer chemistry》2012,50(10):2068-2074
A series of novel nonmetallocene catalysts with phenoxy‐imine ligands was synthesized by the treatment of phthaldialdehyde, substituted phenol with TiCl4, ZrCl4, and YCl3 in THF. The structures and properties of the catalysts were characterized by 1H NMR and elemental analysis. These catalysts were used for copolymerization of ethylene with acrylonitrile after activated by methylaluminoxane (MAO). The effects of copolymerization temperature, Al/M (M = Ti, Zr, and Y) ratio in mole, concentrations of catalyst and comonomer on the polymerization behaviors were investigated in detail. These results revealed that these catalysts were favorable for copolymerization of ethylene with acrylonitrile. Cat. 3 was the most favorable one for the copolymerization of ethylene with acrylonitrile, and the catalytic activity was up to 2.19 × 104 g PE/mol.Ti.h under the conditions: polymerization temperature of 50 °C, Al/Ti molar ratio of 300, catalyst concentration of 1.0 × 10–4 mol/L, and toluene as solvent. The resultant polymer was characterized by FTIR, cross‐polarization magic angle spinning, 13C NMR, WAXD, GPC, and DSC. The results confirmed that the obtained copolymer featured high‐weight–average molecular weight, narrow molecular weight distribution about 1.61–1.95, and high‐acrylonitrile incorporation up to 2.29 mol %. Melting temperature of the copolymer depended on the content of acrylonitrile incorporation within the copolymer chain. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
15.
A New Aluminum/Nickel/Oxo‐Cluster: [Ni(acac)OAl(OtBu)2]4 When bis(tert‐butoxy)alane (tBu‐O)2AlH is allowed to react with nickeldiacetylacetonate at elevated temperature a new nickel/aluminum/oxo cluster [Ni(acac)OAl(OtBu)2]4 is formed together with aluminum acetylacetonate Al(acac)3 and some other products. The metal/oxo cluster is isolated by crystallization and structurally fully characterized by X‐ray diffraction analysis. The molecule [Ni(acac)OAl(OtBu)2]4 contains an eight membered Al4O4 cycle, to which eight mutually edge sharing NiO2Al cycles are fused. The overall point symmetry of the metal/oxo cluster is almost S4. While the aluminum atoms are tetrahedrally surrounded by oxygen ligands (mean distances Al‐O in‐between 1, 730(6) and 1, 789(6) Å)), the nickel atoms are in a square pyramidal coordination sphere of oxygen atoms (Ni‐Oaxial = 1.938(6) Å, Ni‐Obasal = 2.056(9) Å; all polyhedra are distorted). The nickel atoms have a d8 high spin electron configuration (μeff = 3.32 B.M.). 相似文献
16.
Yoichi Inubushi Ryoji Takami Mitsunobu Iwasaki Hiroaki Tada Seishiro Ito 《Journal of colloid and interface science》1998,200(2):220
The mechanism of formation of nanocrystalline ZnO particles from the reaction of zinc acetylacetonate ([Zn(acac)2]) with 2-equivalent NaOH in boiling EtOH was investigated by characterizing the particles and following the transformation of acac moieties. The reaction was found to proceed via hydrolysis of zinc ethoxide derivatives, followed by dehydration–condensation reactions. High-resolution solid-state CP-MAS13C NMR measurements indicate that the ZnO particles are produced through Zn (acac)(OZn)n(acac) (3). Furthermore, it was suggested that acac−ligands play an important role in the generation of nanocrystalline ZnO particles by suppressing the hydrolysis–condensation of Zn(acac)(OZn)n(acac). 相似文献
17.
A novel metallocene catalyst was prepared from the reaction of (η3‐pentamethylcyclopentadienyl)dimethylaluminum (Cp*AlMe2) and titanium(IV) n‐butoxide Ti(OBu)4. The resulting titanocene Cp*Ti(OBu)3 was combined with methylaluminoxane (MAO)/tri‐iso‐butylaluminum (TIBA) to carry out the syndiotactic polymerization of styrene. The resulting syndiotactic polystyrene (sPS) possesses high syndiotacticity according to 13C NMR. Catalytic activity and the molecular weight of the resulting sPSs were discussed in terms of reaction temperature, concentration of MAO, amounts of scavenger TIBA added, and the hydrogen pressure applied during polymerization. 相似文献
18.
S. Hayase T. Ito S. Suzuki M. Wada 《Journal of polymer science. Part A, Polymer chemistry》1981,19(10):2541-2550
The polymerization of cyclohexene oxide with Al(acac)3-silanol catalyst supported by zeolite and porous silica has been investigated. Cyclohexene oxide was also polymerized to a lesser extent by a zeolite-silanol catalyst and an Al(acac)3-silica gel catalyst. The catalytic activity of the zeolite-silanol system varied with the zeolite pore size. The catalytic activity of the Al(acac)3-silanol system was enhanced by supporting the catalyst with porous silica or zeolite. The Al(acac)3-silanol catalyst supported by zeolite was especially effective in increasing polymer conversion and molecular weight. Catalytic activity increased with increasing chemical interaction between silanol and porous silica. The molecular weight of the polymers with these catalysts increased in the order zeolite-silanol> zeolite-Al(acac)3-silanol >Al(acac)3-silanol ≈ Al(acac)3-silanol supported by porous silica>Al(acac)3-silica gel. 相似文献
19.
The ring‐opening metathesis polymerization of cyclododecene using an electrochemically reduced tungsten‐based catalyst (WCl6? e?? Al? CH2Cl2) is described. In addition, the influence of reaction conditions on the polymerization yield was determined. The resulting polymer has been characterized by NMR, IR, gel permeation chromatography and differential scanning calorimetry. The glass transition temperature and melting point of the polydodecenamer are 19.6°C and 70.0°C respectively. Furthermore, cyclododecene has been polymerized into a low‐molecular‐weight polymer (12.0 × 103) with a polydispersity of 2.06 in high yields (94%). IR and NMR analysis indicate that the polydodecenamer has a high trans content (60%). Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
20.
Coordination Chemistry of [Co(acac)2] with N‐Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co‐O4‐N Species
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jongwoo Han Young Jin Sa Yeonjun Shim Min Choi Prof. Dr. Noejung Park Prof. Dr. Sang Hoon Joo Prof. Dr. Sungjin Park 《Angewandte Chemie (International ed. in English)》2015,54(43):12622-12626
Hybridization of organometallic complexes with graphene‐based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the reaction of an organometallic complex, [CoII(acac)2] (acac=acetylacetonate), with N‐doped graphene‐based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt‐containing species is coordinated to heterocyclic groups in N‐doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co‐O4‐N structure. 相似文献