Gd@C82(OH)40 has been developed as a new generation of MRI contrast agent. But recently, it was found that Gd@C82(OH)x with a larger number of OH (x>36) would lead to cage break and hence, release of highly toxic Gd ions. We synthesized the more stable Gd@C82(OH)x with less OH-number, Gd@C82(OH)16, and studied its proton relaxivity and MRI images. The results indicate that Gd@C82(OH)16 also gives high proton relaxivity, even higher than that of (NMG)2-Gd-DTPA. The bio-distribution indicated that Gd@C82(OH)16 tends to be entrapped in the liver and kidney and remained in tissue for about 2 hours. The results suggest that the more
stable metallofullerene derivative Gd@C82(OH)16 can be the potential candidate of the new MRI contrast agent. 相似文献
Solutions of endohedral Gd@C82(C2v) and Ho@C82(C2v) metallofullerenes are studied by means of visible and near-IR spectroscopy upon their conversion from neutral to the anionic form via a redox reaction with the electron donor potassium perchlorotriphenylmethide K(18-crown-6)[C(C6Cl5)3]. The concentrations of the studied solutions of endohedral Gd@C82(C2v) and Ho@C82(C2v) metallofullerenes in o-dichlorobenzene were determined from the spectroscopic data, and their molar extinction coefficients are calculated.
The structural energies of the endohedral derivatives of buckminsterfullerenes Gd@C60(CHR)2 and Gd@C80(CHR)2 were calculated by quantum-chemical methods – semiempirical PM3 and nonempirical RHF SCF MO LCAO with the S. Huzinaga MINI
minimum basis set and GAMESS software. 相似文献
Herein, A549 tumor cell proliferation was confirmed to be positively dependent on the concentration of Fe3+ or transferrin (Tf). Gd@C82(OH)22 or C60(OH)22 effectively inhibited the iron uptake and the subsequent proliferation of A549 cells. The conformational changes of Tf mixed with FeCl3, GdCl3, C60(OH)22 or Gd@C82(OH)22 were obtained by SAXS. The results demonstrate that Tf homodimers can be decomposed into monomers in the presence of FeCl3, GdCl3 or C60(OH)22, but associated into tetramers in the presence of Gd@C82(OH)22. The larger change of SAXS shapes between Tf+C60(OH)22 and Tf+FeCl3 implies that C60(OH)22 is bound to Tf, blocking the iron‐binding site. The larger deviation of the SAXS shape from a possible crystal structure of Tf tetramer implies that Gd@C82(OH)22 is bound to the Tf tetramer, thus disturbing iron transport. This study well explains the inhibition mechanism of Gd@C82(OH)22 and C60(OH)22 on the iron uptake and the proliferation of A549 tumor cells and highlights the specific interactions of a nanomedicine with the target biomolecules in cancer therapy. 相似文献
The electronic properties of the metal atoms encaged in a fullerence cage were investigated using synchrotron X-ray photoelectron
spectroscopy. Systematic variations in photoemission of valence band of Gd@C82, Gd@C82(OH)12, and Gd@C82(OH)22 were observed in Gd 5p levels. The results suggest that the electronic properties of the inner metal atom can be efficiently
modulated by surface chemistry of the fullerene cage. 相似文献
We quantum chemically explore the thermodynamics and kinetics of all 65 possible mechanistic pathways of the Bingel–Hirsch addition of dimethyl bromomalonate to the endohedral metallofullerene La@C2v‐C82 that result from the combination of 24 nonequivalent carbon atoms and 35 different bonds present in La@C2v‐C82 by using dispersion‐corrected DFT calculations. Experimentally, this reaction leads to four singly bonded derivatives and one fulleroid adduct. Of these five products, only the singly bonded derivative on C23 could be experimentally identified unambiguously. Our calculations show that La@C2v‐C82 is not particularly regioselective under Bingel–Hirsch conditions. From the obtained results, however, it is possible to make a tentative assignment of the products observed experimentally. We propose that the observed fulleroid adduct results from the attack at bond 19 and that the singly bonded derivatives correspond to the C2, C19, C21, and C23 initial attacks. However, other possibilities cannot be ruled out completely. 相似文献
An efficient method for the synthesis of trifluoromethyl derivatives of endohedral gadolinium-containing metallofullerenes
was proposed. High-purity (98–99%) trifluoromethyl derivatives Gd@C82(CF3)5 (two isomers) and Gd2@C80(CF3) have been synthesized for the first time. They were isolated and characterized by HPLC, MALDI-TOF mass spectrometry, and
UV-Vis spectroscopy.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1457–1462, July, 2008. 相似文献
Sonochemical reduction of copper nitrate, using 20 kHz ultrasound in aqueous solutions in the presence of urea, led to the formation of layered copper hydroxy nitrate nanosheets, as evidenced by scanning and transmission electron microscopy images. Fourier‐transform infrared, X‐ray diffraction, and X‐ray photoelectron spectroscopy analyses were used to characterize layered Cu2(OH)3NO3 nanosheets. The ultrasound‐assisted progressive hydrolysis of urea and in situ formation of Cu(0) through the sonochemical reduction process induced homogeneous nucleation and crystallization of layered Cu2(OH)3NO3 nanosheets. 相似文献
Isomerically pure endohedral metallofullerene Dy@C82(C2v) was synthesized by the electric arc method, extracted from the soot with o-dichlorobenzene, isolated from the extract by HPLC, and characterized by mass spectrometry and spectrophotometry. The spectrophotometric titration of a solution of endohedral metallofullerene Dy@C82(C2v) was conducted with potassium perchlorotriphenylmethide. The concentration of Dy@C82(C2v) in o-dichlorobenzene was determined, and the molar absorption coefficients for its neutral and anionic forms were calculated (3.0?103 (at 927 nm) and 4.0?103 mol–1 L cm–1 (at 884 nm), respectively. 相似文献
The first pyrrolidine and cyclopropane derivatives of the trimetallic nitride templated (TNT) endohedral metallofullerenes Ih‐Sc3N@C80 and Ih‐Y3N@C80 connected to an electron‐donor unit (i.e., tetrathiafulvalene, phthalocyanine or ferrocene) were successfully prepared by 1,3‐dipolar cycloaddition reactions of azomethine ylides and Bingel–Hirsch‐type reactions. Electrochemical studies confirmed the formation of the [6,6] regioisomers for the Y3N@C80‐based dyads and the [5,6] regioisomers in the case of Sc3N@C80‐based dyads. Similar to other TNT endohedral metallofullerene systems previously synthesized, irreversible reductive behavior was observed for the [6,6]‐Y3N@C80‐based dyads, whereas the [5,6]‐Sc3N@C80‐based dyads exhibited reversible reductive electrochemistry. Density functional calculations were also carried out on these dyads confirming the importance of these structures as electron transfer model systems. Furthermore, photophysical investigations on a ferrocenyl–Sc3N@C80‐fulleropyrrolidine dyad demonstrated the existence of a photoinduced electron‐transfer process that yields a radical ion pair with a lifetime three times longer than that obtained for the analogous C60 dyad. 相似文献
Cisplatin is a commonly used chemotherapeutic drug in cancer treatment, whereas Gd@C82(OH)22 is a new nanomaterial anti-tumor agent. In this study, we determined intracellular Gd@C82(OH)22 and cisplatin after treatment of Hela and 16HBE cells by single cell inductively coupled plasma-mass spectrometry (SC-ICP-MS), which could provide quantitative information at a single-cell level. The cell digestion method validated the accuracy of the SC-ICP-MS. The concentrations of Gd@C82(OH)22 and cisplatin in cells at different exposure times and doses were studied. The SC-ICP-MS is a promising complement to available methods for single cell analysis and is anticipated to be applied further to biomedical research.
Ni(OH)2 nanoflowers were synthesized by a simple and energy‐efficient wet chemistry method. The product was characterized by scanning electron microscopy (SEM) and X‐ray powder diffraction (XRD). Then Ni(OH)2 nanoflowers attached multi‐walled carbon nanotubes (MWCNTs) modified glassy carbon electrodes (GCE) were proposed (MWCNTs/Ni(OH)2/GCE) to use as electrochemical sensor to detect hydrogen peroxide. The results showed that the synergistic effect was obtained on the MWCNTs/Ni(OH)2/GCE whose sensitivity was better than that of Ni(OH)2/GCE. The linear range is from 0.2 to 22 mmol/L, the detection limit is 0.066 mmol/L, and the response time is <5 s. Satisfyingly, the MWCNTs/Ni(OH)2/GCE was not only successfully employed to eliminate the interferences from uric acid (UA), acid ascorbic (AA), dopamine (DA), glucose (GO) but also NO2? during the detection. The MWCNTs/Ni(OH)2/GCE allows highly sensitive, excellently selective and fast amperometric sensing of hydrogen peroxide and thus is promising for the future development of hydrogen peroxide sensors. 相似文献
A new strategy for the non‐chromatographic extraction of metallofullerenes from solutions of arc‐processed raw soot is based on the size‐selective complexation with cycloparaphenylene (CPP). [11]CPP has a high affinity for Mx@C82 (x=1, 2); for example, Gd@C82 can be selectively extracted from a fullerene mixture by the addition of [11]CPP. This approach should open new opportunities in metallofullerene chemistry, including for the bulk extraction of metallofullerenes. 相似文献
Synthesis, Complex Formation and Crystal Structures of Cyclotriphosphazenes with Pyridylalkylamino Groups A variety of cyclotriphosphazenes with different numbers and types of functional pyridylalkylamino groups were synthesized by reactions of chlorophosphazenes with aminoalkylpyridine derivatives and completely characterized. The molecular structures of one multifunctional N‐donor ligand, N3P3(OC6H5)5(NHCH2CH2C5H4N‐2) ( 1 ), was determined by X‐ray structure analysis. The hexafunctionalized derivative N3P3(NHCH2CH2C5H4N‐2)6 ( 10 ) reacts with dichloromethane to form the HCl salt ( 10 a ) the structure of which could also determined by X‐ray crystal structure analysis. Complex formation of N3P3(OC6H5)5(NHCH2C5H4N‐3) ( 2 ) with cobalt(II) chloride yields the cobalt complex ( 2 a ) in which two molecules of the ligand are bonded to the tetrahedraly coordinated cobalt atom by the pyridine nitrogen atoms. The tetra functionalized ligand gem‐N3P3(OC6H5)2(NHCH2CH2C5H4N‐2)4 ( 8 ) forms the dinuclear cobalt‐cobaltate complex ( 8 a ) by interactions of a phosphazene nitrogen atom and the pyridine atoms of two cis‐vicinal functional groups with a CoCl unit and a pyridine group with a CoCl3‐unit. 相似文献
Cyclic voltammogram (CV) and differential pulse voltammogram (DPV) of Gd@C82 were measured by using mixed solvent system and low temperature. The sixth and seventh electron transfers for Gd@C82 were observed under this condition. Analysis of its electrochemical data and the changes of its UV–VIS–NIR spectrum indicated that Gd@C82(n−) (n=1,3) anions had been generated by chemical method. 相似文献
Sulfanilamide derivatives of the type RØSO2NHR in which substitution at both the amino and amido nitrogen have been synthesized where R = NHCOCH:CHCOOH, NHCOCH2CH2COOH, NHCH2CH(OH)CH2SO3Na, N+(CH3)3I? and NHCH2CH(OH)CH2N+(C2H5)3Cl? and R′ = butyl, cyclohexyl, and decyl. The unique structural features of these sulfanilamides were confirmed by infrared, proton magnetic resonance and elemental analysis. Most of these compounds exhibited good water solubility and surface activity. Wetting ability and tendency of enhancing oil/water emulsification were related to the structure of the substituents in sulfanilamide molecule. Furthermore, the peculiar of molecular structure of these sulfanilamide surfactants imparts distinguished antimicrobial activity to these molecular species against some Gram positive and Gram negative bacteria. 相似文献
The synthesis and single‐crystal X‐ray structural characterization of the first endohedral metallofullerene to contain a heptagon in the carbon cage are reported. The carbon framework surrounding the planar LaSc2N unit in LaSc2N@Cs(hept)‐C80 consists of one heptagon, 13 pentagons, and 28 hexagons. This cage is related to the most abundant Ih‐C80 isomer by one Stone–Wales‐like, heptagon/pentagon to hexagon/hexagon realignment. DFT computations predict that LaSc2N@Cs(hept)‐C80 is more stable than LaSc2N@D5h‐C80, and suggests that the low yield of the heptagon‐containing endohedral fullerene may be caused by kinetic factors. 相似文献
The endohedral lanthanidofullerenes, an important type of organolanthanides, are stabilized by the delocalization of the negative charges on the cages of fullerenes. Since the discovery of these classes of carbon compounds and their unusual structures and properties of these molecules, many potential applications have been suggested. Unsaturated thiocrown ethers with cis-geometry are a group of crown ethers that, in light of the size of their cavities and their conformational restriction compared to a corresponding saturated system (1–9), demonstrate interesting properties for physicochemical studies. Endohedral lanthanidofullerenes M@Cx (x = 82 and M = Ce, Gd) were introduced as a new class of the spherical fullerene group with unique properties. Formation of endohedral metallofullerenes is thought to involve the transfer of electrons from the encapsulated metal atom(s) to the surrounding fullerene cage. Two of these molecules are the Ce@C82(10) and Gd@C82(11). The supramolecular complexes of 1–9 with Ce@C82(10) and Gd@C82(11) have been shown to possess a host–guest interaction for electron transfer processes, and these behaviors have previously been reported. Topological indices have been successfully used to construct effective and useful mathematical methods for finding good relationships between structural data and the various chemical and physical properties. To establish a good structural relationship between the structures of 1–9 and M@Cx that were introduced here, an index that is represented as μcs was utilized. This index is the ratio of summation of the number of carbon atoms (nc) and the number of sulfur atoms (ns) to the product of these two numbers for 1–9. In this study, the relationship between this index and oxidation potential (oxE1) of 1–9, as well as the free energy of electron transfer (ΔGet, by the Rehm-Weller equation) between 1–9 and 10 and 11 as [X-UT-Y][Ce@C82] (12) and [X-UT-Y][Gd@C82] (13) complexes, is presented. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献