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 15 毫秒
1.
Co2(CO)8 and Te2O react to form the well known Co4(CO)10Te2, Co4(CO)11Te2 complexes and the two new cluster complexes CCo6(CO)12Te2(1), and CCo6(CO)10Te2(Te3) (2). The structures of 1 and 2 were determined by X-ray analysis, together with the triphenylphosphine derivative of 1, CCo6(CO)11(PPh3)Te2(3), which was analyzed to clarify the disordered structure of the parent compound. Complex 1 is formed by a prismatic cluster of cobalt atoms with a carbon embedded in the cage; two tellurium atoms cap the triangular faces of the prism and each cobalt atom links two terminal carbonyl groups. The complex 2 has a similar prismatic cage CCo6; two 4-Te atoms cap two rectangular faces of the prism, while other two Te atoms bridge two edges of the triangular faces and are linked each other through a third Te atom. Electron counting gives for complex 2 92 electrons: the presence of two long Co–Co distances suggests that the two excess electrons are located on Co–Co antibonding orbitals. Crystal data for 1, space group C2/c, a = 12.845(2) Å, b = 13.449(2) Å, c = 13.246(2) Å, = 91.95(2)°, Z = 4, R = 0.097 for 2555 reflections; for 2, space group Pnna, a = 17.219(5) Å, b= 14.969(6) Å, c = 9.178(4) Å, Z = 4,R = 0.037 for 3103 reflections; for 3, space group P21/c, a = 9.288(2) Å, b = 14.920(6) Å, c = 26.300(9) Å, = 99.99(2)°, Z = 4, R = 0.037 for 4300 reflections. The vibrational analysis of the complex 1 was performed and most of the (CO), (6C–Co), (Co–Co) and (Co–Co) modes were assigned. The (Co–Te) modes were interpreted on the basis of the intermolecular coupling, due to the close contact between neighboring clusters in one distinct direction in the crystal.  相似文献   

2.
SynthesisandCharacterizationofThermotropicLiquidCrystallineComplexesContainingFerrocenylGroupZhanMeiLIU;WeiLIAN,HaiXiaSHI;Ton...  相似文献   

3.
IntroductionRecentresearcheffortshavebeendevotedtothestudyoflatetransitionmetalcomplexesasmodelsystemsforthepolymerizationoroligomerizationofethylene .1 3ThemostnotableachievementshavebeendonebyBrookhart,4 Bennett,5andGibsongroups .6,7Theyinde pendentlyrepor…  相似文献   

4.
The chiral triplesalen ligand H6chand provides three chiral salen ligand compartments in a meta‐phenylene arrangement by a phloroglucinol backbone. The two diastereomeric versions H6chandRR and H6chandrac have been used to synthesize the enantiomerically pure chiral complex [(FeCl)3(chandRR)] ( 3RR ) and the racemic complex [(FeCl)3(chandrac)] ( 3rac ). The molecular structure of the free ligand H6chandrac exhibits at the terminal donor sides the O‐protonated phenol–imine tautomer and at the central donor sides the N‐protonated keto–enamine tautomer. The trinuclear complexes are comprised of five‐coordinate square‐pyramidal FeIII ions with a chloride at the axial positions. The crystal structure of 3rac exhibits collinear chiral channels of ~11 Å in diameter making up 33.6 % of the volume of the crystals, whereas the crystal structure of 3RR exhibits voids of 560 Å3. Mössbauer spectroscopy demonstrates the presence of FeIII high‐spin ions. UV/Vis spectroscopy is in accordance with a large delocalized system in the central backbone evidenced by strong low‐energy shifts of the imine π–π* transitions relative to that of the terminal units. Magnetic measurements reveal weak intramolecular exchange interactions but strong magnetic anisotropies of the FeIII ions. Complexes 3rac and 3RR are good catalysts for the sulfoxidation of sulfides providing very good yields and high selectivities with 3RR being enantioselective. A comparison of 3RR and [FeCl(salen′)] provides higher yields and selectivities but lower enantiomeric excess values (ee values) for 3RR relative to [FeCl(salen′)]. The low ee values of 3RR appeared to be connected to a strong ligand folding in 3RR , opening access to the catalytically active high‐valent Fe–O species. The higher selectivity is assigned to a cooperative stabilization of the catalytically active high‐valent Fe–O species through the phloroglucinol backbone in the trinuclear complexes.  相似文献   

5.
6.
Dong  Mei  GUO  Rui  Qiang  KOU 《中国化学快报》2003,14(2):151-154
In this work,a novel sugar-containing copolymer was synthesized by the copolymerization of α-allyl glucoside(AG) with acryloniutrile(AN).The copolymers were characterized by NMR Spectroscopy.It was found that acrylonitrile-based copolymers containing as high as 22wt.% of α-allyl glucoside can be synthesized by the free radical solution copolymerization of the two monomers in DMSO with AIBN as initiator.  相似文献   

7.
Abstract

Complexes of gallium bound to chalcogen elements recently have found importance in synthesis and as single molecular precursors for preparing thin films of gallium chalcogenides for their applications as photo-receivers for visible and near IR region. Herein we report the synthesis and characterization of some Lewis base (LB) stabilized gallium-telluride complexes. Gallium tellurolate complexes of formula, [LB] · [Ga(TePh)3] x , [x = 1, LB = 4-dimethylaminopyridine; x = 2, LB = 4,4′-methylene bis(N,N′-dimethylaniline] were prepared by reacting the corresponding Lewis base adduct of gallium(III) iodide and phenyllithium tellurolate. The complexes have been characterized by elemental analyses, ICP-MS, multinuclear NMR, and thermal and mass spectrometry. Such complexes may be potential single-molecular precursors for III–VI electronic materials.  相似文献   

8.
SUN  Qiao-Zhen 《结构化学》2011,30(9):1355-1360
A new hexanuclear silver (I) compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence spectrum. The title compound crystallizes in triclinic, space group P with a = 11.611(3), b = 15.610(5), c = 15.624(7) , α = 113.942(6), β = 104.520(6), γ = 104.230(4)°, V = 2304.1(14) 3, C60H77Ag6N22O4.5S6, Mr = 2018.02, Dc = 1.454 g/cm3, μ(MoKα) = 1.435 mm-1, F(000) = 1005, Z = 1, the final R = 0.0468 and wR = 0.1474 for 6608 observed reflections (I > 2σ(I)). In the structure, the S atom of the ligand L2 (L2 = benzaldehyde thiosemicarbazone) served as a triply bridged chelator to connect the six silver atoms into a Ag6L26 cluster. The luminescence property of compound 2 was investigated at room temperature.  相似文献   

9.
Ferrocene and the derivatives play an important role in organometallic chemistry due to their potential novel functions and applications. Of particular interest is an electron-transfer system of ion center for molecular electronics1. Several efforts have been directed towards the design and synthesis of multi-electron redox mediators that could transfer several electrons simultaneously at the same potential2. It was reported that ferrocenylphenyl group was an excellent electron transfer mediat…  相似文献   

10.
A diorganotin(IV) complex [(CH3)2Sn]3L2(L=N'-acetylsalicyl-hydrazide) 1 has been successfully synthesized and structurally characterized by elemental analysis,FT-IR,NMR(1H,13C and 119Sn) spectra and X-ray crystallography.The crystal structure belongs to an orthorhombic system,space group Pnma with a=8.5047(16),b=28.466(5),c=12.842(2) ,V=3109.1(10)3,C24H32N4O6Sn3,Mr=828.61,Dc=1.770 g/cm3,μ(Mo-Kα)=2.432 mm-1,Z=4,F(000)=1608,the final R=0.0378 and wR=0.0973 for 2125 observed reflections(Ⅰ 2σ(Ⅰ)).The complex is a trinuclear organotin(Ⅳ) containing five-and six-coordinated tin atoms.And weak but significant Sn···O intermolecular interactions lead to the assembly of complex into a 1D linear polymeric chain supramolecular framework.  相似文献   

11.
The titanyl complex, TiO(C22H22N4), a complex of the ligand (I) obtained by the hydrolysis of the corresponding dichloride, has a reactive Ti=O function which readily interacts with other metal species forming μ-oxo heterobinuclear dimers. In these adducts, the Ti=O functions as a base toward oxophilic metal centres such as Fe(lII) and as a π-acid, analogous to the carbonyl group, forming an adduct with a low valent species such as the Mo(CO)5 group, yielding a Ti(IV)-O-Mo linkage. Crystals of the titanyl complex, TiO(C22H22N4).C2O2H6, are monoclinic, P21/C with a = 23.083(3), b = 7.740(7), c = 23.208(5) Å, β = 96.54. (2) and d(calcd) = 1.443 g cm ?3 for Z = 4. The Ti=O distance is 1.653(3) Å with a large displacement of 0.754(3) Å for the Ti atom from the N4 macrocyclic coordination plane. The adduct of the titanyl complex with Fe(SALEN)Cl, SALEN = (salicylaldimine)ethylenediamine, in the presence of NaB(C6H5)4 yields a μ-oxo-heterobinuclear complex_of stoichiometry (C22H22N4)Ti-O-Fe- (SALEN)B(C6H5)4. Crystals of the complex are triclinic, P1 with a = 13.122(4), b = 13.883(12), c = 14.539(5) Å, a = 94.21(5), β = 93.08(3), γ = 99.46(3)° with d(calcd) = 1.336gem?3 for Z = 2. In addition to the expected dimeric Ti-O-Fe structure, weak interactions between the SALEN oxygen atoms and the iron atom of the centrosymmetrically related Fe(SALEN) group yields a tetrameric cluster, The Ti-O distance of the Ti-O-Fe linkage is lengthened to 1.706(4) Å and the Fe-O distance is 1.935(6) Å with the Ti-O-Fe angle 160.9(2)°. The Fe-O “intramolecular” interaction distance, 2.178 Å, is indicative of a weak bond.  相似文献   

12.
The two new compounds (NH4)2[Cu5(H2O)10(DCTA)2] [β-Mo8O26]·4H2O (1) and Cu2[Cu3K2(H2O)10(DCTA)2(HBW12O40)]·14H2O (2) (DCTA = 1,2-diaminocyclohexanetetraacetate anion) were synthesized in aqueous solutions and characterized by elemental analyses, TGA, IR spectroscopy and single-crystal X-ray diffraction technique. Single-crystal structure analyses indicate they are constructed by the complexes with different nuclearity and polyoxometalates. In 1 DCTA chelates Cu2 ion and bridges Cu1 and Cu3 ions, forming a tetra-nuclear-ring cation chain extending along [110] direction. In 2 DCTA chelates Cu2/Cu1 and combines Cu3 and K ions, leading to a cyclic ten-heteronuclear complex cation; the K2 ions combine the complex cations and BW12O40 5? anions, forming a complex cation-BW12 layer extending on ab-plane. The variable-temperature magnetic susceptibilities of newly prepared crystalline sample of 1 were measured and 1 exhibits a weak antiferromagnetic interaction.  相似文献   

13.
The novel perfluorinated vinyl ether containing sulfonimide functionality CF2 = CFORfSO2NHSO2CF3 was synthesized by multiple reaction steps. It could be copolymerized with tetrafluoroethylene by radox initiator to give a novel perfluorinated ionomer polymer. Its physical and chemical properties were studied.  相似文献   

14.
A new titanium-silicate material was synthesized with cubic cage-like tetramethylammonium octasilicate and TiCl4 ethanol solution as precursors. The product was characterized by FTIR, ^29Si NMR, UV-Vis, and XRD. Struc-tural and ingrediental analyses suggest that this material has a layered structure with cubic cage-like polyhedral oligo-silsesquioxane as building blocks and titanium as bridging atoms.[第一段]  相似文献   

15.
Abstract

A series of new nitrogen heterocyclic compounds containing sulfur–ether (8a–8f) and Schiff-base (9a–9q) functionalities were synthesized by the reaction of the pharmaceutical lead compound containing both benzimidazole and 1,2,4-triazole rings. The compounds were characterized by 1H NMR, 13C NMR, FT-IR, HR-MS, and ESI-MS.  相似文献   

16.
In this study, the ability of Cupriavidus sp. USMAA2-4 to synthesize polyhydroxyalkanoates (PHA) containing 4-hydroxyvalerate monomer (4HV) was studied through one-stage cultivation using γ-valerolactone as the carbon precursor. The presence of 4HV monomer unit in the polymer was detected through gas chromatography analysis, proving the capability of this wild strain bacterium to produce poly(3-hydrxybutyrate-co-3-hydroxyvalerate-co-4-hydroxyvalerate) [P(3HB-co-3HV-co-4HV)] terpolymer. Existence of a 4HV monomer unit in the PHA produced was further confirmed through 13C and 1H NMR analysis. P(3HB-co-88 % 3HV-co-1 % 4HV) terpolymer with the highest PHA content of 63 wt% was obtained through combination of 0.14 wt% C of γ-valerolactone with 0.42 wt% C of oleic acid. Various compositions of P(3HB-co-3HV-co-4HV) terpolymer with 3HV and 4HV compositions ranging from 11 to 94 mol% and from 1 to 4 mol%, respectively, were acquired by manipulating γ-valerolactone and oleic acid concentrations. The molecular weight and the thermal and mechanical properties of four different compositions of terpolymers—P(3HB-co-91 % 3HV-co-1 % 4HV), P(3HB-co-55 % 3HV-co-2 % 4HV), P(3HB-co-27 % 3HV-co-2 % 4HV), and P(3HB-co-9 % 3HV-co-1 % 4HV)—were characterized. Among these terpolymers, P(3HB-co-27 % 3HV-co-2 % 4HV) terpolymer with a molecular weight of 5.7 (105 Da) exhibited the highest elongation to break (264 %). The monomer unit compositional distributions of these terpolymers were investigated through acetone–water fractionation analysis. The results suggested that these produced terpolymers had broad 3HV compositional distribution and narrow 4HV compositional distribution.  相似文献   

17.
The reaction of K[Co(CO)4] and PCl2(TMP) at –5°C leads to the unstable and reactive -phosphinidene complex [Co2(CO)6{-P(TMP)}] (1), while the same reaction carried out at 35°C gives the chlorophosphido and phosphinidene bridged cluster [Co3(CO)7{-P(Cl)TMP}{ 3-P(TMP)}] (2) (TMP=2,2,6,6-tetramethylpiperidyl). Compound 1 reacts with dppm (dppm=bis(diphenyl- phosphino)methane) and [Co2(CO)8] to form the more stable substitution product [Co2(CO)4{-P(TMP)}(-dppm)] (3) and [Co4(CO)7(-CO)3{ 3-P(TMP)}] (4) respectively. The first example of a cationic 3-phosphinidene cluster compound [Co3(CO)9{ 3-P(TMP)}][AlCl4] (5) is obtained from reaction of 3 with AlCl3. The X-ray structures of clusters 2 and 5 are discussed.  相似文献   

18.
A novel thiophene-bridged donor–acceptor system was synthesized with a carbazole as donor and a borole as acceptor unit. The borole group was successfully installed via the tin–boron exchange reaction of 1,1-dimethyl-2,3,4,5-tetraphenylstannole with 9-(5-(dibromoboryl)thiophen-2-yl)carbazole. The effect of the borole on the optoelectronic properties of the donor–acceptor system was explored by spectroscopic (UV/Vis and fluorescence spectroscopy), electrochemical (cyclic voltammetry) and theoretical (TD-DFT) methods as well as by modifying its structure. The corresponding donor–acceptor compound bearing the widely employed dimesitylboryl acceptor group was also synthesized for comparison.  相似文献   

19.
The electrical properties of sol–gel-derived films can be tailored by embedding conductive particles of ruthenium dioxide or carbon black in an insulating amorphous SiO2 silica matrix. The preparation process included an acid hydrolysis of tetraethoxysilane and methyltrimethoxysilane. Then alcohol solutions of ruthenium chloride or carbon black were added. Films of filler concentration up to 60 vol.% were prepared by dip coating and then dried and heat-treated at various temperatures up to 600_°C. The D.C. resistance of the films can be varied within the range of 109 to 10–2 cm. A non-linear dependence on filler composition in the films was observed for both systems, which is explained by a modified percolation theory. A percolation threshold of 5.5 vol.% for SiO2-RuO2 or 50 vol.% for SiO2-C films, whereby the resistance drastically decreases, was determined. Moreover the temperature dependency of resistance and the current-voltage characteristics of the films can also be explained by this geometric model.  相似文献   

20.
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