首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
方志刚  胡红智 《无机化学学报》2006,22(12):2222-2228
With the level of B3LYP/Lanl2dz of density functional theory and advisable adsorption models designed, the adsorption properties of the most stable cluster of Ni2Fe2P were calculated, and four stable configurations with the adsorption of hydrogen were gained. The geometries and HOMO contributions of 3d orbital of metal atoms and energy level properties of adsorption configurations were concerned and their Infrared Spectrum were simulated and predicted. The bond lengths and bond orders and vibration frequencies concerned synthetically, the adsorption mechanisms of hydrogen molecular on amorphous alloys Ni40Fe40P20 surfaces were discussed in the microcosmic aspect. The hydrogen molecules adsorbing on the clusters were dissociated. In the clusters′ Infrared Spectrums of hydrogen adsorption, there were the vibration peaks with the frequency less than 500 cm-1 caused by metal atoms and other vibration peaks with the frequency more than 500 cm-1 caused by hydrogen atoms. Compared with the energy level DOS of the clusters before and after adsorption, it was found, that the new adsorption activity sites generated after the adsorption of hydrogen, as well as easy way for metal atoms providing electrons and participating subsequence reactions were gained.  相似文献   

2.
The single-crystal of [CuCo(TS)(H2O)·H2O],where TS is the schiff base N,N'-bis(3-carboxylsalidene)trimethylenediamine, was obtained and its crystal structure was determined by the single-crystal X-ray diffraction method at room temperature. It crystallizes in the monoclinic system, space group P21/c. The lattice parameters are a=11.855(2)?, b=14.722(3)?, c=12.080(2)?, β=117.32(3)°, V=1879.4(7)?3 , Z=4 with R1=0.0330. The structure is made of heterobinuclear units . The copper atom is coordinated by two nitrogens, two phenolic oxygens, in a square-planar manner. And the cobalt atom is coordinated by two phenolic oxygen atoms, two equatorial carboxyl oxygen atoms and one axial water oxygen atom, in a distorted square pyramid. Two metal atoms are bridged by two phenolic oxygens. In the crystal packing, the neutral molecules built layers. Within these layers the molecules are connected through hydrogen bonds. And the thermal property of the complex according to crystal structure is also investigated.  相似文献   

3.
A coordination polymer of [Zn(BBP)(p-CPOA)]n(where BBP is 2,6-bis(benzimidazolyl)pyridine and p-CPOA is p-carboxylato-phenoxyacetate dianion) has been synthesized and characterized by elemental analysis, IR, TG, and the single crystal structure was determined by X-ray diffraction. The crystal crystallizes in the monoclinic system, space group of P21/n with a=1.397 3(4) nm, b=1.138 4(3) nm, c=1.575 9(5) nm, β=91.805(1)°, V=2.505 4(13) nm3, Z=4, Dc=1.513 g·cm-3, μ=1.030 mm-1 and F(000)=1 168. Zn(Ⅱ) ion is penta-coordinated and surrounded by two carboxylate O atoms from two different p-CPOA groups in a bis-monodentate mode, three N atoms from the 2,6-bis(benzimidazolyl)pyridine ligand, completing a distorted trigonal bipyramidal coordination configuration. The structure is a helix with a long pitch of 1.138 4 nm. Under direction of supramolecular recognition and attraction, the adjacent chains are formed the double-stranded chain through π-π stacking between the 2,6-bis(benzimidazolyl)pyridine ligands and hydrogen-bonding interactions. A three-dimensional supramolecular network is further constructed through these interactions between the helices. The TG shows that its chain skeleton is thermally stable up to 382 ℃. CCDC: 626650.  相似文献   

4.
A new one-dimensional compound [Cd(dafo)(SCN)2]n(dafo=4,5-diazafluoren-9-one) has been synthesized and characterized by single crystal X-ray diffraction. It crystallizes in the orthorhombic system; space group Pbca with a=1.708 6(5), b=1.303 6(4), c=2.592 6(8) nm, V=5.775(3) nm3, and Z=16. The crystal structure revealed that the structure of [Cd(dafo)(SCN)2]n features μ-1,3-thiocyante bridges and 1D chains. It consists of octahedrally coordinated Cd atoms. Both Cd(1) and Cd(2) are surrounded by two nitrogen atoms from dafo, two S atoms and two N atoms from two di-μ-1,3 thiocyanato bridges. CCDC: 251185.  相似文献   

5.
纳米尖晶石LixMn2O4的制备与电化学性能表征   总被引:11,自引:0,他引:11  
Nano-spinel LixMn2O4(0.6 ≤x≤ 1.0) was synthesized by two steps of coprecipitation and calcination. The influences of calcination temperature, time and Li/Mn ratio on the crystal structure and the particle size of LixMn2O4 were investigated. It was shown that the higher the calcination temperature, the more complete the crystal structure, and the larger the particle size. Moreover, the influence of calcination time on the crystal structure was insignificant when it was more than 3h at 700℃. With the increase of x in LixMn2O4 in the range of 0.6~1.0, the d111 and lattice parameter a increased first and then decreased. The electrochemical properties of nano-spinel LiMn2O4 using as cathode material of lithium-ion battery were studied. The low discharge capacity might be due to the irreversible capacity loss brought by the large surface area and lattice vacancies of the nano-spinel.  相似文献   

6.
[Mn(ECZ)3](NO3)2 is newly prepared by the aqueous solutions of Mn(NO3)2 and ethyl carbazate (ECZ). The crystal structure has been determined by X-ray crystal diffraction analysis. It belongs to monoclinic with space group of P21/n. The crystal parameters are: a=1.3974(2) nm, b=0.8796(2) nm, c=3.4322(7) nm, β=91.25(1) °, V= 4.2175(1) nm3, Z=8. Its molecular weight is 491.30. Mn2+ is located on the center of the molecular structure. Ethyl carbazate serves as a bidentate ligand which coordinates to the metal cations with its carbonyl oxygen atom and the terminal hydrazine nitrogen atom, forming five-member chelating rings, and three such rings are formed in each molecule. The coordination number of the metal ion is six and the coordination configuration of the central ion is octahedral. Specially, antimer configuration phenomenon is found in the molecule. The complex is further characterized by element analysis and IR measurements. The thermal decomposition mechanism is studied by using TG-DTG and DSC techniques. CCDC: 215675.  相似文献   

7.
A novel coordination polymer [Zn(N3)2(bpp)]n[bpp=1,3-bis(4-pyridyl)-propane] was synthesized at room temperature and structurally characterized by means of X-ray single crystal diffraction. The results show that the polymer exhibits a linear chain structure; the Zn-Zn distance is 12.235?. Each Zn(Ⅱ) ion is coordinated by two nitrogen atoms from bpp ligands and two nitrogen atoms from azido (N3-) groups, the coordination geometry of Zn(Ⅱ) ion is a slightly distorted tetrahedron, the angles around Zn(Ⅱ) ions are from 103.27° to 121.37°. In the solid-state structure of the polymer, the linear chains are stacked with parallel mode along a direction. Moreover, between adjacent chains, there are π-π interactions between pyridine rings, which are arranged in face-to-face fashion with interplanar distances of av. 3.821?. CCDC: 189591.  相似文献   

8.
水菱钇型碳酸钕的形成及聚甘油脂肪酸酯对结晶的影响   总被引:2,自引:0,他引:2  
Amorphous Neodymium carbonate was prepared by the precipitation reaction of neodymium chloride with ammonium bicarbonate in solution, and then aged at 60 ℃ to form crystalline neodymium carbonate. The feed molar ratio of n(NH4HCO3)/n(NdCl3 was 2.5, and the precipitation was carried out with or without addition of polyglyceryl fatty acid ester (PGFAE). The phase type and morphology of crystalline neodymium carbonates were examined by XRD and SEM, and the effect of PGFAE on the crystallization speed was investigated by volume change in deposit layer and in situ pH determination. The content of neodymium and chloride in crystals was analyzed, and the crystallization reaction or crystal growth characteristics were discussed. It was found that all the crystalline neodymium carbonates were tengerite type, and contained less crystalline water and chloride than that of lanthanite type neodymium carbonate crystallized at room temperature, which is beneficial to the production of neodymium carbonate with higher neodymium and lower chloride content. The addition of PGFAE not only could eliminate the foam formed during precipitation, but also could shorten crystallization time, and form large radiative-like shape conglomeration by the irregulative linkage of one dimension needle crystals. It is also suggested that the morphology and the chloride content of neodymium carbonate were dependent on the structure and crystal growth characteristics.  相似文献   

9.
郝仕油 《无机化学学报》2007,23(8):1477-1480
Nanometer Ce1-xLaxO2-δ solid solutions were synthesized by microwave-induced combustion process us-ing cerium nitrate hexahydrate, lanthanum nitrate hexahydrate and urea as raw materials. The process took only six minutes to obtain La2O3-doped CeO2 nanopowders. The nanopowders were characterized by XRD, Laser Raman spectrum , UV-Vis spectroscopy,field-emission scanning electron micrograph(FE-SEM)and TEM. The results revealed that the grain size of Ce1-xLaxO2-δ varied from 20 to 40 nm calculated by Scherer formula through the plane of (111), that oxygen vacancy was produced in the crystal lattices and the concentration of oxygen vacancy was increased with La doping, therefore the covalence of Ce-O bond was strenthened, which results in more intensive UV-C(200~280 nm)absorption. It can be seen from SEM that the porous appearance was obtained. Grain size is no more than 40nm observed from TEM.  相似文献   

10.
正钛酸胶溶法制纳米TiO2薄膜及性能表征   总被引:7,自引:0,他引:7  
The Nanometer TiO2 thin film was prepared by sol method with titanic acid precursor from industrial TiOSO4 solution. The characters of the sol and the factors affecting sol formation were investigated by ζ electricity potential. The crystalline structure, particle size, appearance shape and photo-catalytic activity were characterized by XRD, SEM, TEM and spectrophotometer. The study show: (1) pH value and HNO3concentration effected importantly on the forming process and stability of the sol. The thermodynamic condition for forming sol is pH=0.5~1.5. The lower the HNO3concentration,the more stable the sol. The ζ electricity potential of the sol, with 5% HNO3as gluing reagent, was up to 48 mV, and shelf life of the sol could more than 10 months. (2) The film, made from the sol and crystallized at 400 ℃, had the characters of anatase structure and crystal size of 18.5 nm by XRD analysis. The SEM imagines show that TiO2 film was with the characteristics of tight surface structure, The TEM imagine showed the mean particle size is about 20 nm. The photo-degrading test data indicate that the photo-degrading rate to methyl orange solution of 20 mg·L-1 was more than 84% in 5 hours.  相似文献   

11.
A novel one-dimension coordination polymer [HgI2(btx)]n was synthesized through the reaction of alpha, alpha’-dichloro-p-xylene and HgI2 in mixed MeOH-THF (1∶1) solution. The compound was characterized by X-ray crystallography and crystallizes in orthorhombic with space group Pnma. The cell parameters of the title compound are: a=0.936 3(2) nm, b=1.769 4(4) nm, c=1.032 2(2) nm, α=90°. Attractive I…I interactions link HgI2(btx) chains directly resulting in the formation of three-dimensional network structure. In addition, the compound shows better luminescence spectroscopic property in the solid state, and is thermally stable below 126 ℃. CCDC: 233053.  相似文献   

12.
The complex, Ni[(C13H7Br2NOS)2(DMF)]·(C3H7O) (DMF=N,N′-dimethylformamide), was synthesized and characterized by the element analysis, IR and X-ray diffraction single crystal structure determination. The title complex crystallizes in monoclinic system, space group P21/n, with a=8.297 6(15) nm, b=12.866(2) nm, c=31.889(3) nm, β=95.024(2)°, and V=3 391.3(9) nm3, Z=4, R=0.075 2, wR=0.176 8. The nickel iron is six-coordinated by three O atoms, two N atoms, one S from the Schiff base and one O atom from DMF ligand, forming a octahedron coordination geometry. Schiff bases are bridged by the two S atoms. The molecules in the crystal are linked through intermolecular Br…Br, C-H…O, S…Br interactions. Its electrochemical property is reported. CCDC: 675768.  相似文献   

13.
一维链状铜(Ⅱ)配合物的合成及晶体结构表征   总被引:1,自引:0,他引:1  
The 1D-chain polymer of [Cu(Ⅱ)3L3(H2O)]n, (H2L=3-(3,5-dichloro-2-hydroxybenzylid-eneamino)propanoic acid) has been synthesized by reaction of 3,5-dichlorosalicylaldehyde, β-alamine and copper nitrate in ethanol solution. The crystal structure was determined by X-ray diffraction method. The crystal structure belongs to mono-clinic system with space group C2/c and cell parameters: a=3.853 7(3) nm, b=0.777 38(18) nm, c=2.656 36(2) nm, β=116.924(2)° and V=7.095 4(17) nm3, Mr=998.85, Z=8, Dc=1.870 g·cm-3 and F(000)=3 992. The two Cu(Ⅱ) atoms are coordinated with four atoms from Schiff base, and another one is coordinated with five atoms. The square bridging links three metal centers through a novel μ-4,4,5 coordination model, which is further assembled into 1D chain coordination polymer. The 1D chain is further constructed a 3D network by strong O-H…O and C-H…O hydrogen bonds. The coordination polymer presents a good thermal stable property through the thermal analysis. CCDC: 679005.  相似文献   

14.
The structure default of kaolinites was characterized with 1H MAS NMR and Raman spectra. Although the HI indexes of Suzhou and Maoming kaolinite are similar, their 1H MAS NMR and Raman spectra are very different. 1H MAS NMR showed that the hydroxyl proton chemical shifts of Suzhou kaolinite are in the higher field and with larger different between the inner surface hydroxyls protons and inner hydroxyls proton chemical shifts than Maoming kaolinite. Raman spectra showed that the surface hydroxyls stretching vibration bands of Suzhou kaolinite are in the high frequency region, and the half height widths of the bands are 7.0~14 cm-1. The area ratio Sz/(Sz+SA), where SZ and SA are the areas of bands 3685 cm-1 and 3695 cm-1 respectively, is 0.23. But the surface hydroxyls stretching vibration bands of Maoming kaolinite are in the low frequency region, and the half height widths of the bands are 8.9~15.1 cm-1. The area ratio Sz/(Sz+SA) is 0.77. Those data proved that Suzhou kaolinite has lower structure default than Maoming kaolinite and 1H MAS NMR and Raman spectra are effective method for study of kaolinite structure default.  相似文献   

15.
5-Chloro-2-methoxybenzoates of heavy lanthanides and yttrium were obtained as di- or tetrahydrates with a metal to ligand ratio of 1:3 and general formula: Ln(C8H6ClO3)3nH2O, where n=2 for Ln=Tb, Dy, Y and n=4 for Ln=Ho, Er, Tm, Yb, Lu. The complexes were characterized by elemental analysis, IR and FIR spectra, thermogravimetric studies, X-ray diffraction and magnetic measurements. The carboxylate group appears to be a symmetrical, bidentate, chelating ligand. All complexes are polycrystalline compounds. Their thermal stabilities were determined in air and in nitrogen atmospheres. When heated they dehydrate to form anhydrous salts which next in air are decomposed to the oxides of the respective metals while in nitrogen to the mixtures of carbon and oxides or carbon and oxychlorides of respective metals. The complexes are more stable in air than in nitrogen. The solubilities of yttrium and heavy lanthanide 5-chloro-2-methoxybenzoates in water at 293 K are of the order of 10–3 mol dm–3 The magnetic moments of the complexes were determined over the range 77–298 K. They obey the Curie–Weiss law. The values of μeff calculated for all compounds are close to those obtained for Ln3+ by Hund and Van Vleck. The results indicate that there is no influence of the ligand field of 4f electrons on lanthanide ions and the metal ligand bonding is mainly electrostatic in nature. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

16.
In the present paper,one hundred cluster models NinBP (n=1~6) have been designed and studied by density functional theory (DFT) to get an insight into the local structure,catalytic properties and sulfur resistibility of amorphous alloy Ni-B-P. The configurations in triplet state are found more stable than those in the singlet state. It is found that as the content of Ni in the clusters increases,the value of Fermi level in clusters fluctuated,which shows that the content of Ni can influence the Fermi level to a certain extent. Based on the Fermi level and DOS,we consider the activity of catalyst in hydrogenation reaction is the best in cluster Ni3BP. On the basis of the charge of clusters NinBP (n=1~6),we conclude the amorphous alloy Ni-B-P with high Ni content has better sulfur resistibility and the best hydrogenation activity,strong sulfur resistibility appears in clusters Ni3BP,and the amorphous alloy Ni60B20P20 with similar proportion is expected to prepare in the future.  相似文献   

17.
A novel one-dimensional coordination polymer, [Ca(μ-p-HPO)2(NO3)2]n, (p-HPO=p-pyridone) was synthesized and characterized by the element analysis, IR, TG and X-ray single crystal diffraction. It crystallizes in the monoclinic space group C2/c with unit cell parameters: a=1.992 1(4) nm, b=0.374 96(7) nm, c=1.930 3(4) nm, β=109.21(3)°. V=1.361 6(5) nm3, Z=4, R=0.034 9, wR=0.084 4. The Ca atom is eight-coordinated by four O atoms from different p-pyridone ligands and four O atoms from two chelating nitrate anions, and displays a distorted square pyramidal coordination geometry. Each p-pyridone ligand bridges two adjacent Ca atoms, forming a infinite chain along the b direction. The Ca…Ca distance is 0.374 96(7) nm. A layer structure is further constructed by intermolecular hydrogen bonds and π-π interactions. The result of TG analysis shows that the title complex is stable under 185 ℃. CCDC: 241576.  相似文献   

18.
The novel seven-coordinate complex [(n-Bu)2Sn(C10H8N2O3)(C2H5OH)]2 (C10H8N2O32- is the dinegative ion of 2-oxo-propionic acid benzoyl hydrazone) was synthesized by the reaction of (n-Bu)2SnO with 2-oxo-propionic acid benzoyl hydrazone in 1∶1 molar ratio in benzene-ethanol (V/V, 3/1), and its structure was characterized by X-ray single crystal diffraction. The crystal belongs to a tetragonal system with space group I41/a, a=2.4890(2)nm, b=2.4890(2)nm, c=1.5170(3)nm, V=9.398(2)nm3, Z=8, F(000)=3968, Dc=1.366g·cm-3, and the structure was refined to final R1=0.0530, wR2=0.0971. The structure of the title complex is described as a dimer through weak interactions of Sn…O bonding and hydrogen bond. The tin atoms rendered sev-en-coordination in a distorted pentagonal bipyramid geometry structure, four oxygen atoms [O1, O2, O2#1 and O4] and one nitrogen atom N2 formed the equatorial plane and C11-Sn1-C15 is the axis. CCDC: 212696.  相似文献   

19.
LaFe0.8-xCuxNi0.2O3 (x=0.0~0.2) (LFCN), a new cathode material of solid oxide fuel cell (SOFC), was synthesized by Co-precipitation method using sodium bicarbonate. The lattice structures of samples with different x contents were characterized by XRD. Porosity and density of the porous LaFe0.8-xCuxNi0.2O3 (x=0.0~0.1) as a function of sintering temperature were investigated. It was found that the orthorhombic structure could be formed after calcination at 900 ℃ for 4 h. The particle size of LFCN was about 350 nm. The density of the porous LFCN increased with sintering temperature, but the opposite was true for the porosity. On the other hand, at the same sintering temperature, the porosity of LaFe0.8-xCuxNi0.2O3 (x=0.0~0.1) decreased with increasing x contents. It is indicated that the dopant of Cu on LaFe0.8Ni0.2O3 can facilitate the sintering of the materials. After sintering at 1 100 ℃ for 4 h, the porous LaFe0.7Cu0.1Ni0.2O3 was still with appropriate structure, and its porosity was 29%.  相似文献   

20.
A coordination polymer [Co(dpa)prz0.5]n(1) with double-helix chains has been constructed hydrothermally using H2dpa (H2dpa=diphenic acid), prz (prz=piperazine) and Co(NO3)2·6H2O. The structure and magnetic properties of the complex were investigated. The complex crystallizes in triclinic system and P1 space group. Each Co atom is five-coordinated and takes a distorted tetragonal pyramid geometry. Two carboxylates of the H2dpa ligands bridge four Co(Ⅱ) ions to form infinite right-handed or left-handed helical -C-O-Co- chains. The two types of helical chains are interconnected to each other through the Co(Ⅱ) centers to produce double-helix chains. The chains form a 2D sheet through the coordination interaction of prz molecules between adjacent chains. The sheets are further interlinked by hydrogen bond interactions to generate 3D coordination frameworks. Magnetic studies for complex 1 show stronger antiferromagnetic coupling between the Co(Ⅱ) ions. CCDC: 709275.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号