[60]富勒烯环加成反应研究进展

综述了[60]富勒烯[2 1]环加成反应、[2 2]环加成反应、[2 3]环加成反应以及[4 2]环加成反应的典型反应、反应试剂以及反应机理,并展望了富勒烯的研究前景和发展方向.     

Ionizable (Thia)calix[4]crowns as highly selective 226Ra2+ ionophores

The 226Ra2+ selectivity of the ionizable (thia)calix[4]crowns 1-4 was determined in the presence of a large excess of the most common alkali and alkaline earth cations. Selective 226Ra2+ (2.9 x 10(-)(8) M) extraction occurs even at extremely high M(n+)/226Ra2+ ratios of 3.5 x 10(7) [M(n+) = Na+, K+, Rb+, Cs+, Mg2+, Ca2+, and Sr2+ (1M)] and an ionophore concentration of 10(-4) M. The selectivity coefficients log(K(Ra)(ex)/K(M)(ex)) are approximately 3.5 for Mg2+, Ca2+, and Sr2+. In the presence of Ba2+, which has very similar chemical properties, only the thiacalix[4]crown-6 derivative 4 showed a selectivity for 226Ra2+. In addition to the remarkable 226Ra2+ selectivities, the effective pH range (pH 8-13) of the thiacalix[4]crown dicarboxylic acids (3 and 4) allows for full regeneration of the ionophores at lower pH values (pH <6).     

Regiochemistry of Azide Additions to [70]Fullerene

In this paper we report for the first time on the reaction of C₇₀ with alkyl azides and show that the [3+2]-cycloaddition occurs preferably at bond 7 followed by bond 5 to give two regioisomeric A/B-triazolines and one C/C-triazoline Thermal extrusion of N₂ from these triazolines leads to open [5,6]-bridged iminofullerenes as A/A- and B/C-isomers as well as to the ring closed [6,6]-bridged analogues as A/B- and C/C-isomers. These results are in line with the corresponding thermal reaction of C₇₀ with diazomethane.     

Regiochemistry of Azide Additions to [70]Fullerene

Abstract

In this paper we report for the first time on the reaction of C₇₀ with alkyl azides and show that the [3+2]-cycloaddition occurs preferably at bond 7 followed by bond 5 to give two regioisomeric A/B-triazolines and one C/C-triazoline Thermal extrusion of N₂ from these triazolines leads to open [5,6]-bridged iminofullerenes as A/A- and B/C-isomers as well as to the ring closed [6,6]-bridged analogues as A/B- and C/C-isomers. These results are in line with the corresponding thermal reaction of C₇₀ with diazomethane.     

Sonochemical reaction of fullerene[C60] with several 2'-azidoethyl per-O-acetyl glycosides

Cycloadditive reaction of fullerene[C60] with various 2'-azidoethyl per-O-acetyl glycopyranoside of D-mannose, D-galactose, D-glucose, D-xylose and D-maltose, respectively gave the glycosyl fullerene[C60] derivatives 2a-2e such as alpha-D-mannosyl fullerene[C60] under ultrasonication. Based on analyses using 1H- and 13C-NMR, UV-vis, FT-IR, and FAB-MS spectroscopies of the glycosyl fullerene[C60] derivatives, the products were composed of a mixture of [5,6]- and [6,6]-junction isomers which were predominantly the closed [5,6]-junction isomer.     

Transition metal cations extraction by ester and ketone derivatives of chromogenic azocalix[4]arenes

The molecule of azocalix[n]arene is a macrocyclic used effectively in the complexation of the heavy metal pollutants (like silver and mercury). In this work, our main aim is to prepare new chromogenic azocalix[n]arene molecules to elaborate an extractant with high extractant selectivity for metal ions able to detect this type of pollutant. The solvent extraction properties of four acetyls, four methyl ketones and four benzoyls derivatives from azocalix[4]arenes which were prepared by linking 4-ethyl, 4-n-butyl, 4-acetamid anilin and 2-aminothiazol to calix[4]arene through a diazo-coupling reaction, the alkaline earth (Sr2+) and the transition (Ag+, Hg2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Cr3+) metal cations have been determined by extraction studies with metal picrates. Both ketones are better extractants than esters, and show a strong preference for Ag+, while Cu2+ and Cr3+ are the most extracted cation with the esters. Both acetyl and benzoyl esters are good carriers for Ag+ and Hg2+.     

Chlorosulphonyl Group as a New Functionality on Fullerenes: [2 2]-Cycloaddition of Chlorosulphonylisocyanate to C60

The chlorosulphonylisocyanate reacts smoothly with C₆₀ in xylene under thermal conditions in a [2+2]-cycloaddition fashion to yield the bisadduct as one of the products in the inseparable reaction mixture. The reaction product is analysed by FAB-MS, ¹³C NMR, FT-IR and HPLC techniques. Results show the formation of imino-lactone as one of the favourable products.     

Self-assembled monolayer of a redox-active calix[4]arene: voltammetric recognition of the Ba2+ ion in aqueous media

The Redox-active monolayer of a novel calix[4]arene recognizing redox-inactive ionic species by voltammetry is reported. Calix[4]arene-disulfide-diquinone, which is not only redox-active but is also a highly selective ionophore for the Ba2+ ion, spontaneously forms a stable and dense monolayer film on gold. The redox-active calixarene monolayer selectively recognizes Ba2+ ion in aqueous media, and the voltammetric signals are proportional to the ionic concentration. A new voltammetric peak can be detected by square-wave voltammetry upon adding a dilute solution containing Ba2+ ion having a concentration as low as 1.0 x 10(-6) M. The Langmuir plot (1/ip vs 1/[Ba2+]) shows a linear slope in the range from 1.0 x 10(-6) M to 1.0 x 10(-4) M. This modified electrode does not show any significant interference from alkali and alkaline earth metal ions except for Sr2+ and Ca2+. Only 100- and 500-fold concentrations of Sr2+ and Ca2+ ions, respectively, can lead to voltammetric responses comparable to that of Ba2+.     

Kinetic Behavior of Addition Reactions to [60]Fullerene

The addition reactions of [60]fullerene to benzyl amine and anthracene were studied by using spectrophotometry. The kinetic measurements show minima if the absorbance at a wavelength of 595 nm is plotted versus time. The minima obtained from the spectrophotometric kinetic measurements can be attributed to the formation of intermediates of C₆₀ due to the single-electron transfer mechanism for the amine addition and electron deloalization processes for the concerted [2 + 4]cyclo-addition.     

Pyrolytic Trifluoromethylation of [76]-, [78]-, [84]-, and Aza[60]Fullerenes with Silver Trifluoroacetate; Evidence for Coordination of Fullerenes to Silver

Pyrolytic trifluoromethylation of [76], [78], [84], and aza[60]fullerenes with silver trifluoroacetate at 300°C results in extensive polyaddition of up to 18, 18, 20 and 20 CF₃ groups, respectively. In contrast to trifluoromethylation of [60]- and [70]fullerenes that give a full range of derivatives ranging upwards from C_n(CF₃)₂, [76]-, [78]-, and [84]-fullerenes only give C_n(CF₃)_6-18 derivatives, largely in the 10-12 CF₃ range; reaction with [76]fullerene is accompanied by formation of C₆₀(CF₃)₆ attributed to cage fragmentation. For aza[60]fullerene the hexa-addition level dominates, in contrast to its other reactions which give predominantly penta-addition products. All the compounds showed peaks at 1256±2 and 1180-1190 cm^-1, due to the CF₃ group, and peaks in this region are shown also by the soluble extract obtained on trifluoromethylation of nanotubes. As in trifluoromethylation of [60]- and [70]-fullerenes, the products obtained initially are involatile, attributed to formation os silver complexes; these are decomposed on subsequent solution in toluene. Mixed isomeric trifluoromethylated C₆₀F₈ derivatives viz. C₆₀F₇CF₃, C₆₀F₆(FG₃)₂, C₆₀F₅(CF₃)₃ and C₆₀F₄(CF₃)₄, and C₆₀F₄CF₃CF₂CF₃ (a C₆₀F₆ derivative) have been isolated from fluorination of [60]fullerene with MnF₃/K₂NilF₆ at 510°C.     

改进型[Cs Rb]2OAg光阴极的制备研究

利用改进工艺制备的[Cs Rb]2OAg光阴极,具有灵敏度高、热发射低和重复性好等优点。特别是改善了变像管的背景亮度。并提出[Cs Rb]2OAg光阴极的表面能带结构模型,对实验结果给予了比较满意的解释。     

Chlorosulphonyl Group as a New Functionality on Fullerenes: [2+2]-Cycloaddition of Chlorosulphonylisocyanate to C60

Abstract

The chlorosulphonylisocyanate reacts smoothly with C₆₀ in xylene under thermal conditions in a [2+2]-cycloaddition fashion to yield the bisadduct as one of the products in the inseparable reaction mixture. The reaction product is analysed by FAB-MS, ¹³C NMR, FT-IR and HPLC techniques. Results show the formation of imino-lactone as one of the favourable products.     

Nanoencapsulation of [60]Fullerene with the Cavitand Cucurbit[7]uril

Novel supramolecular nanocapsules consisting of [60]fullerene and the macrocycle cucurbit[7]uril via self-assembly are reported. The nanocapsules, which were synthesized in a two-phase reaction at room temperature, were obtained in good yields. The stoichiometry of the product was found to be 1:2.     

Diels-Alder Reactions of the [60]Fullerene: From Regularly Functionalized Carbon Spheres to Cyclophanes

Diels-Alder reactions allow the regioselective preparation of various derivatives of the [60]fullerene (1) with exohedral functionalization. A symmetric sixfold [2+4]-cycloaddition of 1,3-dienes to 1 opens direct synthetic access to hydrocarbons with a novel cyclophane structure.     

Thioether crown complexes as templates for the assembly of extended polyiodide networks: synthesis and structures of {[M([16]aneS4)]2I}I11 (M = Pd,Pt), [Pd(cis-HO)2[14]aneS4)](I3)2, [Pd([9]aneS3)2](Ix)2 (x = 3, 5)

Pd(II) and Pt(II) complexes of [16]aneS₄ and Pd(II) complexes of cis-(HO)₂[14]aneS₄ and [9]aneS₃ have been used as templates for the self-assembly of polyiodide ions. The complexes {[M([16]aneS₄)]₂I}I₁₁ (M = Pd, Pt), [Pd(cis-(HO)₂[14]aneS₄)](I₃)₂, [Pd([9]aneS₃)₂](I_x)₂ (x = 3, 5) have been synthesized and structurally characterized. In {[M([16]aneS₄)]₂I}I₁₁, the polyiodide network consists of fused 14-member polyanion rings made up of interacting “L”-shaped I₅⁻ and I⁻ units; binuclear [([16]aneS₄)M–I–M([16]aneS₄)]³⁺ complex cations featuring a highly unusual linear and symmetric M–I–M moiety are each surrounded by one of these 14-member polyiodide rings in a belt-like fashion. The structures of [Pd(cis-(HO)₂[14]aneS₄)](I₃)₂ and [Pd([9]aneS₃)₂](I₃)₂ both feature tri-iodides as counter-anions. In [Pd(cis-(HO)₂[14]aneS₄)](I₃)₂, quite asymmetric I₃⁻ ions form sinusoidal infinite chains via head-to-tail I₃⁻⋯I₃⁻ interactions; these chains run along the (001) direction and are stacked along the (100) direction to form highly puckered anionic layers via I⋯I weak interactions that cross-link the chains. In [Pd([9]aneS₃)₂](I₃)₂, [Pd([9]aneS₃)₂]²⁺ cations are bridged on each side by pairs of symmetric I₃⁻ ions through long-range S⋯I contacts to form discrete infinite ribbons that run parallel to the a axis. By contrast, the structure of [Pd([9]aneS₃)₂](I₅)₂ consists of highly puckered polyanionic layers featuring fused 18-member polyiodide rings made up of I₅⁻ ions. Two of these layers related by an inversion center are stacked along the b axis and interact with each other to form large cavities within which the complex cations sit. In these complex arrays the cation can be regarded as a template around which polyanion networks can be structured. The solid state FT-Raman spectra of the reported polyiodides are discussed on the basis of their crystal structures.     

Stone-Wales Rearrangement Pathways from the Hinge-Opened [2+2] C60 Dimer to Ipr C120 Fullerenes. Vibrational Analysis of Intermediates

Possibility of the previously proposed hinge-opened product 2 of [2+2] C₆₀, dimer 1 transforming itself into IPR C₁₂₀ fullerenes by a series of generalized Stone-Wales (GSW) rearrangements has been tested by seeking all topologically acceptable pathways with the help of a graphical search program. the first IPR isomer 4 appeared after 20 GSW steps from the wide-bridged dumb-bell shaped precursor 3. More than 1,000 C₁₂₀ fullerene structures were generated during subsequent ten GSW steps, but the outstanding T_dC₁₂₀ global minimum 5 was not reached. Semiempirical vibrational calculations predict characteristic transition in the vibrational spectra in the course of rearrangement pathway.     

Diels-Alder Reactions of the [60]Fullerene: From Regularly Functionalized Carbon Spheres to Cyclophanes

Abstract

Diels-Alder reactions allow the regioselective preparation of various derivatives of the [60]fullerene (1) with exohedral functionalization. A symmetric sixfold [2+4]-cycloaddition of 1,3-dienes to 1 opens direct synthetic access to hydrocarbons with a novel cyclophane structure.     

Thermal Transformation of Ring-Opened [2 2] C60 Dimer into a Wide-Bridged C120 Isomer. A Computational Evaluation of Fulvalene-Naphthalene Rearrangements

As a continuation of the studies on thermal transformation of the [2+2] C₆₀ dimer (1), the consequence of the pyracylene-rearrangement-like valence isomerization of the fulvalene partial structure at the bridge of the ring-opened product from 1, namely 2, was searched by dynamic reaction coordinate /AM1 semiempirical MO calculations. It is predicted that the fulvalene bridge of 2 rearranges into naphthalene partial structure by the concerted 'in-plane' mechanism to give a wide-bridged C₁₂₀ intermediate having twenty five-membered rings and two ten-membered rings (3). The computed energy of activation (145 kcal/mol) is 40 kcal/mol lower than those computed for pyracylene rearrangements. In contrast, the recently reported analogous rearrangement of indigo (13) to dibenzonaphthyridindione (14) is computed to occur by the stepwise 'sp³' mechanism.     

苯并[a]芘在表面负载不同金属离子的SY-6活性炭上的脱附活化能

主要研究了苯并[a]芘在金属离子改性活性炭表面的脱附活化能,程序升温脱附实验测定了苯并[a]芘在Fe3+,Zn2+和Ag+等金属改性活性炭上的脱附活化能,并应用软硬酸碱理论分析和讨论了其脱附活化能的差异。结果表明,苯并[a]芘在改性活性炭上脱附活化能的顺序如下:Ag(Ⅰ)/ACACZn(Ⅱ)/ACFe(Ⅲ)/AC。和原始活性炭相比,Ag+增强了苯并[a]芘和活性炭表面间的结合力,Zn2+和Fe3+减弱了苯并[a]芘和活性炭表面间的结合力,并首次用软硬酸碱理论解释了试验结果。     

Comparison of crystallization rates of [Al]-and [Ga]-MFI-type zeolites

The crystallization rates of [Al]- and [Ga]-MFI-type zeolites were studied at 170°C and autogeneous pressure. Samples were characterized by XRD, FTi.r. solid-state ²⁷Al and ⁷¹Ga MAS n.m.r., and X.p.s. techniques. Results clearly show that the crystallization rate of [Ga]-ZSM-5 is much faster than that observed for [AI]-ZSM-5. Whereas [Ga]-ZSM-5 is synthesized in just 4 h, [AI]-ZSM-5 is synthesized in 40 h under the same conditions. This is probably due to the fact that, under alkaline conditions, free gallate ions are more stable than are aluminate ions.