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1.
采用密度泛函理论方法比较了DBT/DBTO2和[BMIM]+[PF6]-/[BMIM]+[BF4]-的相互作用。对最稳定的[BMIM]+[PF6]-、[BMIM]+[PF6]--DBT、[BMIM]+[PF6]--DBTO2、[BMIM]+[BF4]-、[BMIM]+[BF4]--DBT、[BMIM]+[BF4]--DBTO2进行了NBO和AIM分析。结果表明,DBT和[BMIM]+[PF6]-/[BMIM]+[BF4]-中的咪唑环彼此相互平行,NBO和AIM分析表明它们之间发生了π-π相互作用。H1'和H9'形成的F…H氢键有利于π-π堆积作用的形成。DBTO2倾向于趋近C2-H2和甲基基团形成O…H相互作用;DBTO2优先吸附在[BMIM]+[PF6]-/[BMIM]+[BF4]-。在模拟油中,[BMIM]+[PF6]-和[BMIM]+[BF4]-离子液体对DBTO2的萃取能力大于DBT,其原因是可能是DBTO2具有较大的极性和O…H与F…H的氢键作用。  相似文献   

2.
李丹  薛佳丹  郑旭明 《物理化学学报》2014,30(12):2216-2223
通过共振拉曼光谱实验和量子化学计算的方法研究了4-硝基咪唑(4NI)A-带激发态衰变动力学.对4NI的振动光谱、紫外电子吸收光谱、荧光光谱和共振拉曼光谱进行了指认.在全活化空间自洽场法(CASSCF)/6-31G(d)计算水平下获得了单重激发态S1(nOπ*)和S2(ππ*)和势能面交叉点S1(nOπ*)/S2(ππ*)的优化几何结构和能量,分析了A-带共振拉曼光谱的强度模式特征,获得了短时结构动力学,并结合全活化空间自洽场法(CASSCF)理论计算结果确定了4NI在S2(ππ*)态衰变通道主要是S2,FC→S2,min(ππ*)→S0辐射弛豫.  相似文献   

3.
Transamination reactions utilizing the compound mercuric bis(trimethylsilyl)amide, Hg{N(SiMe3)2}2, in tetrahydrofuran (THF), and the metals Na, Mg, Ca, Sr, Ba and Al have been investigated. Thus the THF solvated compounds Na[N(SiMe3)2]·THF and M[N(SiMe3)2]2·2THF, M = Mg, Ca, Sr and Ba (1–4), have been prepared. The X-ray crystal structures of 1 and the related manganese compound Mn[N(SiMe3)2]2·2THF (5) are reported. Interaction of the silylamides, 2–4, with a range of crown ethers apparently proceeded with elimination of silylamine, (Me3Si)2NH, and novel ring opening of the crown ethers, generating species containing a donor alkoxide ligand with a vinyl ether function, presumably, ---O(CH2CH2O)nCH=CH2 (n = 3−5). The silylamides 2–4 were also cleanly converted to the corresponding alkoxides (from 1H NMR data) in reactions with stoichiometric quantities of 3-ethyl-3-pentanol.  相似文献   

4.
The bis(μ3-ethylidyne) tricobalt cluster [(CpCo)33-CCH3)2] (1b) is protonated by trifluoroacetic acid to give the dicobalt edge-protonated cation [H(CpCo)33-CCH3)2]+ [lb + H]+. Protonation of the μ3-ethylidyne tetracobalt cluster hydride [H(CpCo)43-CCH3)] (3) takes place in two consecutive steps. At low temperature [H2(CpCo)43-CCH3)]+ [3 + H]+ is formed first, and is then slowly converted into [H3(CpCo)43-CCH3)]2+ [3 + 2H]2+ by an excess of acid. As judged by the 1H NMR data and the crystal structure of [3 + X]+[(CF3COO)2X] (X = H or D) the endo hydrogens in [3 + H]+ and [3 + 2H]2+ occupy μ3-(Co3) face capping hydridic positions. The cations [1b + H]+ and [3 + H]+ show hydride fluxionality in solution, which in the case of [3 + H]+ can be frozen out on the NMR timescale at low temperature (ΔG (203 K) = 40.8 kJ/mol). The structure of [3 + X]+ [(CF3COO)2X] (X = H or D) was determined by X-ray crystallography. One of the hydrides/deuterides is located on the crystallographic mirror plane, capping a tricobalt face of the cluster cation. The other endo hydrogen atom is believed to be disordered between the other two μ3-(Co3) sites, which are related by space group symmetry. Deuteronation of 3 shows a strong normal kinetic deuterium isotope effect. From the temperature independence of the 1H NMR spectrum of [3 + 2D]2+ a non-fluxional solution structure can be inferred. In all the systems studied, hydridic (μ2- or μ3-) sites are thermodynamically preferred to possible isomeric agostic CoHC or Co2HC sites for the endo hydrogens. Agostic interactions cannot, however, be ruled out in transient intermediates during the course of the protonations.  相似文献   

5.
Upon UV irradiation in hexane at 243 K tricarbonyl-η5-cyclohexadienyl-manganese (1) and two equivalents of 2-butyne (2) or diphenylacetylene (4) yield in successive [5 + 2, 3 + 2] cycloadditions tricarbonyl-η2:2:1-1,2,3,10-tetramethyl-tricyclo[5.2.1.04,9]-deca-2,5-dien-10-yl-manganese (6), or tricarbonyl-η2:2:1-1,2,3,10-tetraphenyl-tricyclo[5.2.1.04,9]-deca-2,5-dien-10-yl-manganese (8), respectively. 3-Hexyne (3) reacts with 1 under the same conditions by successive [5 + 2, 3 + 2] cycloadditions and 1,4-H-shift to tricarbonyl-η2:2:1-1,2,3-triethyl-10-ethylidene-tricyclo[5.2.1.04,9]dec-2-en-5-yl-manganse (7). Identical products are also obtained when 1 is first irradiated in THF at 208 K and the thermolabile intermediate, dicarbonyl-η5-cyclohexadienyl-tetrahydrofurane-manganese (11), is treated with an excess of the alkynes 2–4. In contrast, bis(trimethylsily)acetylene (5) substitutes photochemically in 1 only a CO ligand to yield dicarbonyl-η5-cyclohexadienyl-η2-bis(trimethylsily)Acetylene-manganese (9). The crystal and molecular structure of 7 was determined by an X-ray diffraction analysis. Complex 7 crystallizes in the triclinic space group , a = 822.6(2) pm, B = 882.5(2) pm, C = 1344.6(2) pm, = 92.36(2)°, β = 107.13(2)°, γ = 99.71(2)°, V = 0.9152(3) nm3, Z = 2. The complexes 6–9 were studied in solution by IR and NMR spectroscopy. The structures of 6,8 and 9 were elucidated from the NMR spectra. A possible formation mechanism for the complexes 6–9 will be discussed.  相似文献   

6.
光敏冠醚、苯甲酰苯井-15-冠-5(BPC)和双(4-苯并-15-冠-5)甲酮(CBPC),用光谱方法和动力学方法进行了研究,吸收光谱和发射光谱数据表明,BPC和CBPC的最低激发态具有ππ*特性,它们的光化学性质和烷氧基取代的二苯酮相似,在紫外光照射下,BPC和CBPC很容易和叔胺进行光反应生成自由基碎片,光还原过程用吸收光谱测定进行了跟踪,这些光敏冠醚BPC和CBPC,配合叔胺可用作烯类光聚合的引发剂,测得的聚合速度(Rp)和[BPC]0.17[TEA]0.29及[MMA]0.81成正比。  相似文献   

7.
In this paper, we introduce a simple one-step method to synthesize [2]catenanes incorporating naphthalenediimide and crown ethers by associated interactions of templates. In this functional supermolecular system, the combined hydrogen-bond and π-donor/π-acceptor interactions led production of the [2]catenanes which exhibit reversible moving of the crown ether macrocycle on the big ring between two stations via de/reprotonation. This movement on the big ring can change the electron interaction, resulting in strong quenching of the emission of naphthalene diimide.  相似文献   

8.
Two synthetic routes to a novel class of sterically overcrowded alkenes, bithioxanthylidene crown ethers 1, are described. The 1H spin-lattice relaxation times (T1) of the crown ethers as well as those of the corresponding complexes with Li+, Na+, K+, Rb+ and Cs+ in CDCl3 were measured and the results were interpreted in terms of complexation affinities.  相似文献   

9.
The complexes formed from copper(II) and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP or HL) in aqueous methanol solution was studied by electrospray ionization mass spectrometry. The solution of a 1:1 complex of Cu(II) with 5-Br-PADAP showed five peaks assignable to a binuclear complex [Cu2L2(AcO)]+ and mononuclear complexes [CuL]+, [CuL(H2O)]+, [CuL(AcOH)]+ and [CuL(HL)]+ (AcO=acetate). Collision activated dissociation revealed the relative order of bonding strengths; Cu–L>Cu–HL>CuL–AcOH>CuL–H2O. The peak intensities of the binuclear complex showed second-order dependency on those of the mono complex. As for the solution of Ni(II)–5-Br-PADAP, no binuclear complex was observed in the mass spectra. Thus, it was suggested that [Cu2L2(AcO)]+ was formed by the fast gas phase reaction: 2[CuL]++AcO[Cu2L2(AcO)]+.  相似文献   

10.
Mohapatra PK  Manchanda VK 《Talanta》1998,47(5):2437-1278
Ion-pair extraction behaviour of uranyl ion from aqueous solutions was studied at pH 3.0 employing crown ethers viz. benzo 15 crown 5 (B15C5), 18 crown 6 (18C6), dibenzo 18 crown 6 (DB18C6), and dibenzo 24 crown 8 (DB24C8) in chloroform as the organic phase and picric acid as the organophilic counter anion. The stoichiometry of the extracted species corresponded to [UO2(crown ether)n]2+·[pic]2 where n=1.5 for benzo 15 crown 5 and 1 for 18 crown 6 as well as dibenzo 18 crown 6. Adducts of DB24C8 could not be observed as practically no extraction was possible using this reagent. The separation behaviour of fission products from an irradiated uranium target was also studied. An interesting observation on the separation of trivalent lanthanides from uranyl ion is reported.  相似文献   

11.
Three new gallium complexes formulated as [Ga(PDA)2][Ga(H2O)(PDA)(phen)]·4H2O(1), [Ga(PDA)2]· (H2IN)·2H2O(2) and [Ga(OH)(PDA)(H2O)]2(3)(H2PDA=pyridine-2,6-dicarboxylic acid; phen=1,10-phenanthroline; HIN=isonicotinic acid) have been synthesized under hydrothermal conditions. In the mixed-ligand system of complex 1, PDA2? and phen are connected to the central Ga3+ cation as tri- and bi-dentate ligands, respectively. In complex 2, each Ga3+ cation is six-coordinated by two PDA2? anions octahedrally. Complex 3 shows a binuclear structure, with the bond distance of Ga1-Ga2 being 0.30061(3) nm. The 3D supramolecular structures of the three complexes are constructed via hydrogen bonds and aromatic π-π packing interactions. All the three complexes exhibit intense blue emission at room temperature in the solid state, which are attributed to π*-π transition centered on the ligands.  相似文献   

12.
Photodynamic properties of series of metal complexes having the general formula [M(diars)2X2]ClO4 or BF4 where M = Co3+, Cr3+, Rh3+; X = Cl, Br, I, diars = o-phenylene bis(dimethylarsine) are studied. Photogeneration of singlet oxygen is monitored by both optical and EPR methods. In comparison with rose bengal ((1O2) for RB = 0.76), singlet oxygen generating efficiencies of these complexes are determined. Rate of N,N-dimethyl-4-nitrosoaniline (RNO) bleaching is found to be retarded by specific 1O2 quencher NaN3, confirming the involvement of 1O2 as an active intermediate. Photolysis of these complexes in the presence of spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) generates 12-line EPR spectra, characteristic of O2 adduct. Photogeneration of O2 is also monitored by optical spectroscopy using superoxide dismutase (SOD) inhibitable cytochrome c reduction assay. The results indicate that the [Co(diars)2Br2]ClO4 complex possesses high ability to generate reactive oxygen species (ROS). Both Type I and II paths are involved in the photosensitisation of the metal complexes. The antimicrobial activity of the complexes against selected bacteria is estimated. The relationship between the enzymatic production of ROS and antimicrobial activity of the complexes is examined and a good correlation between two factors is found. The [CoBr2(diars)2]ClO4 complex investigated in this study effect photo cleavage of the plasmid DNA (pUC18).  相似文献   

13.
The oxidation of Cp2MCl2 (M= Mo, W) with perfluortriazinium tetrafluoroborate, [(FCN)3F]+[BF4], in the presence of a flouride ion acceptor (BF3 or PF5) in SO2 solution yielded the cationic metallocene complexes [Cp2MCl 2]2+[BF4] or [Cp2MCl2] 2+[BF4][PF6] (M = Mo, W), respectively. In these reactions, for the first time the perfluortriazinium cation has proved to be easy to handle and a useful oxidizer in organometallic chemistry. The oxidizer strength of three fluorotriazinium cations, [(XCN)3F]+ (X = F, Cl, H), has been computed ab initio (HF/6 − 31 + G) and calibrated on literature data which were obtained by local density functional calculations. It was anchored to its F+ zero point by an experimental value for KrF+. ab]Die Oxidation von Cp2MCl2 mit (M = MO, W) Perfluortriaziniumtetrafluoroborat, [(FCN)3F]+[BF4], in Anwesenheit eines Fluoridionenakzeptors (BF3 oder PF5) führte in SO2-Lösung zur Bildung der kationischen Metallocen-Komplexe [Cp2MCl2+]2+[BF4]2 bzw. [Cp2MCl2]2+[BF4] [PF6] (M = Mo, W). In diesen Reaktionen konnte erstmals gezeigt werden, daß Perfluortriazinium-Kationen einfach zu handhabende und nützliche Oxidationsmittel im Bereich der metallorganischen Synthese darstellen. Das (Mdationsvermögen von drei Fluorotriazinium-Kationen, [(XCN)3F]+(X = F, Cl, H), wurde ab initio berechnet (HF/6 − 31 + G) und mit Hilfe von Literaturdaten, die mittels local density functional-Berechnungen erhalten und am experimentellen Wert von KrF + bezüglich des F+ Nullpunktes verankert wurden, kalibriert.  相似文献   

14.
本文研究了1-苯基-3-甲基-4-苯甲酰基吡唑啉酮-5(PMBP)与丁基膦酸二丁酯(DBBP)或磷酸三丁酯(TBP)的氯苯溶液在硝酸介质中对铽(Ⅲ)的协同萃取。测得了萃合物的组成及其萃取平衡常数,讨论了萃合物的可能结构式及协同萃取机理。  相似文献   

15.
为了探索侧链R基团对碱金属离子与多肽复合物气相裂解反应的影响, 采用电喷雾电离质谱法研究了碱金属离子Li+, Na+和K+分别与甘氨酸三肽(GGG)、 甘氨酰-苯丙氨酰-甘氨酸三肽(GFG)和甘氨酰-甘氨酰-苯丙氨酸三肽(GGF)形成的复合物的气相裂解反应. 质谱定性实验结果表明, Li+, Na+和K+与GGG, GFG或GGF在气相中可以形成稳定的复合物, 配合比为1∶1或2∶1. 竞争反应质谱图显示, GGG, GFG或GGF与碱金属离子形成的复合物的质谱峰丰度按Li+, Na+, K+顺序依次下降, 表明随着碱金属离子半径的增加, 它们与三肽的结合强度依次减弱. 碰撞诱导解离显示, 母体离子[GGG+Na]+, [GGF+Na]+和[GFG+Na]+ 的质心碰撞能量E(CM)50数值分别为1.94, 1.76和1.63 eV. 通过质谱滴定法测得[GGG+Na]+, [GFG+ Na]+和[GGF+Na]+ 的结合常数lgKa1分别为5.30, 5.25和5.17. 质谱法定量结果进一步确认复合物的稳定性顺序为[GGG+Na]+>[GGF+Na]+>[GFG+Na]+, 表明由于空间位阻的影响, 侧链R基团含有苄基的GFG或 GGF与Na+的键合强度要小于侧链R全部为H的GGG. 串级质谱分析结果显示, 碱金属化的GGG断裂位点较多, 可解离出丰富的金属化a2, b和y型碎片离子, 而碱金属化的GGF和GFG解离出的金属化y型离子较多, b型离子其次, 金属化a型离子几乎没有. 此外, 双碱金属化的GGF可解离出较多金属化y型离子. 复合物[GGF+Na]+的裂解曲线显示, 当碰撞能量为25 eV时, [y2+Na-H]+ 和[b2+Na+OH]+为主要碎片离子, 当碰撞能量>40 eV时, 只有[b2+Na+OH]+ 碎片离子占有优势数量. 根据质子化三肽裂解机理可以推测, 钠化GFG裂解后生成含噁唑酮的[b2+Na]+离子, 该离子经过一系列过渡态生成[a2+Na]+(2-苄基-4-咪唑酮), 而不是常见的亚胺离子.  相似文献   

16.
Aiming to identify the spiro metallaaromatic systems with potential application value, (C10H10M)2?(M=Ni, Pd, Pt) derivatives were theoretically investigated. (C10H10M)2?-Iso1, which has two 6-membered rings(6MRs) connected by the M spiro atom, is a 14π-aromatic as a whole plane. (C10H10M)2?-Iso2 has one 6π-aromatic 5MR and one 10π-aromatic 7MR connected by the spiro atom. The free (C10H10M)2? dianions could not exist due to their rather high frontier orbital energies, while the neutral (C10H10M)Li2 compounds are extremely stable against dissociation. Since (C10H10M)Li2 coumponds are not fully coordinated, they trend to form (C10H10M)Li42+ dications, or even[(C10H10M)Li2]n polymers. Arguably, (C10H10M)2? planes are not the only examples for spiro metallaaromaticity, their derivatives are also potential material building blocks.  相似文献   

17.
The crystal structure of bis(trifluoroacetato)-(N-methyl-meso-tetraphenylporphyrinato) thallium(III), Tl(N---Me---tpp)(CF3CO2)2 (2), was established and the coordination sphere around the Tl3+ ion is described as 4:3 tetragonal base–trigonal base piano stool seven-coordinate geometry in which the two cis CF3CO2 − groups occupy two apical sites. The plane of the three pyrrole nitrogen atoms [i.e. N(2), N(3) and N(4)] strongly bonded to Tl3+ is adopted as the reference plane 3N. The pyrrole N(1) ring bearing the methyl group [i.e. C(45)H3] is the most deviated one from the 3N plane making a dihedral angle of 23.3° whereas smaller angles of 9.9, 2.7 and 4.7° occur with pyrroles N(2), N(3), and N(4), respectively. Because of the larger size of the thallium(III) ion, Tl is considerably out of the 3N plane; its displacement of 1.02 Å is in the same direction as that of the two apical CF3CO2 − ligands. The intermolecular trifluoroacetate exchange process for 2 in CD2Cl2 solvent is examined through 19F and 13C NMR temperature-dependent measurements. In the slow-exchange region, the CF3 and carbonyl (CO) carbons of the CF3CO2 − groups in 2 are separately located at δ 114.3 [1J(C–F)=290 Hz, 3J(Tl–C)=411 Hz] and 155.1 [2J(C–F)=37 Hz, 2J(Tl–C)=204 Hz], respectively, at −106 °C. In the same slow-exchange region, the fluorine atoms of 2, Tl(N---Me---tpp)(CF3CO2)+ and the free CF3CO2 − are located at δ −73.76 [4J(Tl–F)=44 Hz], −73.30 [4J(Tl–F)=22 Hz], and −76.15 ppm at −97 °C, respectively.  相似文献   

18.
研究了溶液中杯[4]芳烃双冠-6(BisC6)与Cs+配位行为.常温下,BisC6/NPME(邻硝基苯甲醚)体系单级萃铯百分率达99.36%,模拟料液中,Cs+/Na+和Cs+/K2+分离系数分别为3.92×104和2.21×104.局域结构模型实验表明,配合物分子中可能存在水或(和)硝酸(根).ESI-MS谱表明,NPME体系中,铯离子与BisC6同时形成1:1(单核)和2:1(双核)的配合物,并且存在[BisC6·H2O],[BisC6·Cs+]+,[BisC6·2Cs+·H2O]2+和[BisC6·2Cs10+·No10-3]10+等多种配合物分子.EXAFS实验表明,溶液中铯离子的配位数为7,形成7个氧配位的稳定结构,ADF计算验证了EXAFS实验结果.  相似文献   

19.
The reactions of a wide range of transition-metal carbonyls with anhydrous HF are described. In particular, Ru3(CO)12, Os3(CO)12 and Ir4(CO)12 give the solution stable [Ru3(CO)12H]+, [Ru(CO)5H]+, [Os3(CO)12H]+, [Os(CO)5H]+ and [Ir4(CO)12H2]2+ respectively, which have been characterised by a combination of 1H and 13C NMR spectroscopy.  相似文献   

20.
The hydrophobic ionic liquid (IL) 1-propyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C3mim][NTf2]) was synthesized according to traditional methods. By adding different amounts of diethyl carbonate (DEC) solvent and lithium bis[(trifluoromethyl)sulfonyl]imide ([Li][NTf2]) salt to [C3mim][NTf2] IL, eight solution systems were prepared. First, the thermodynamic properties of the eight solution systems were characterized by differential scanning calorimetry (DSC). The semi-stable temperature of the system gradually disappeared with increasing lithium salt content, but the melting point temperature was not apparent in the experiment. These results indicate that DEC and lithium salts can dissolve in ILs within the tested temperature range. The basic properties of the eight systems, including thermodynamic and dynamic properties, were systematically studied at different temperatures. The variation in the self-diffusion coefficient of lithium ion ([Li]+) as a function of DEC concentration, density changes, viscosity, conductivity, and the viscosity/conductivity activation energy of the eight systems was calculated by the Vogel Fulcher Taman (VFT), Final Vogel Fulcher Taman (FVFT), and Arrhenius equations. The effect of temperature on the properties of the system was studied in detail. Within the temperature range measured herein, the deviation between the fitting equation and experimental value was small. Consequently, these equations were successfully used to calculate the properties of the system at various temperatures. All fitting parameters of the corresponding equations are provided herein. The viscosity for all systems decreased rapidly with increasing temperature, which increased the conductivity. Based on these experiments, the influence of DEC on the system microstructure was discussed in the context of the molecular dynamics simulation results. In particular, the interaction between [Li]+ and [NTf2]-/DEC was examined. In all solution systems, [NTf2]- coordinates to [Li]+ through only the O atom and not the N atom. Radial distribution function (RDF) analysis showed that the interaction between [Li]+ and [NTf2]- weakened with increasing DEC concentration. DEC molecules were observed in the first solvation layer of [Li]+ coordinating to [Li]+ through the carbonyl O atom. Although the interaction between [Li]+ and DEC was weakened, competition between [NTf2]- and DEC in the first solvation layer of [Li]+ was observed by the coordination number analysis of the O atom around [Li]+. Therefore, the introduction of DEC is beneficial for Li+ diffusion, which is consistent with the experimental results.  相似文献   

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