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161.
The paper presents a comparative analysis of the possibilities and characteristic features of the application of various polyhedral boron compounds, viz., the closo-decaborate anion [B10H10]2–, the closo-dodecaborate anion [B12H12]2–, the carba-closo-dodecaborate anion [CB11H12]–, carboranes C2B10H12, and the bis(dicarbollide) complexes [M(C2B9H11)2]– (M = Fe, Co, or Ni), in boron neutron capture therapy (BNCT) for cancer. The requirements on compounds used in BNCT are formulated and the advantages of the application of the closo-dodecaborate anion are considered. The data on the synthesis of various derivatives of the closo-dodecaborate anion, which either already found use in BNCT or are most promising in this field, are summarized. The possibilities of the application of agents derived from the closo-dodecaborate anion in medical diagnostics are discussed. 相似文献
162.
《Journal of Saudi Chemical Society》2020,24(9):673-682
A single dielectric barrier discharge (DBD) low-temperature plasma reactor was set up, and toluene was selected as the representative substance for volatile organic compounds (VOCs), to study the reaction products and degradation mechanism of VOCs degradation by low-temperature plasma. Different parameters effect on the concentration of O3 and NOx during the degradation of toluene were studied. The exhaust in the process of toluene degradation was continuously detected and analyzed, and the degradation mechanism of toluene was explored. The results showed that the concentration of O3 increased with the increase of the power density and discharge voltage of the plasma device. However, as the initial concentration of toluene increased, the concentration of O3 basically keep steady. The concentration of NOx in the by-products increased with the discharge voltage, power density, and initial concentration of toluene in the plasma device, and the concentration of NO2 was much higher than the concentration of NO. The degradation process of toluene was detected and analyzed. The results showed that the degradation mechanism of toluene by plasma includes high energy electron bombardment reaction, active radical reaction and ion molecule reaction. Among them, the effect of high-energy electrons on toluene degradation is the largest, followed by the effect of free radicals, in which oxygen radicals participated in the reaction mainly through the formation of C–O bond, CO bond, (CO)–O– bond and –OH radical, while nitrogen radicals participate in the reaction mainly through the formation of C–NH2, (CNH)- bond, CN bond and C–NO2 bond. The results can provide some data supports for the study of low-temperature plasma degradation of VOCs. 相似文献
163.
Faqiong Zhao Liqin Liu Fei Xiao Jiangwen Li Rui Yan Shuangshuang Fan Baizhao Zeng 《Electroanalysis》2007,19(13):1387-1393
An ionic liquid (i.e., 1‐butyl‐3‐methylimidazolium hexafluorophosphate, BMIMPF6)‐single‐walled carbon nanotube (SWNT) gel modified glassy carbon electrode (BMIMPF6‐SWNT/GCE) is fabricated. At it the voltammetric behavior and determination of p‐nitroaniline (PNA) is explored. PNA can exhibit a sensitive cathodic peak at ?0.70 V (vs. SCE) in pH 7.0 phosphate buffer solution on the electrode, resulting from the irreversible reduction of PNA. Under the optimized conditions, the peak current is linear to PNA concentration over the range of 1.0×10?8–7.0×10?6 M, and the detection limit is 8.0×10?9 M. The electrode can be regenerated by successive potential scan in a blank solution for about 5 times and exhibits good reproducibility. Meanwhile, the feasibility to determine other nitroaromatic compounds (NACs) with the modified electrode is also tested. It is found that the NACs studied (i.e., p‐nitroaniline, p‐nitrophenol, o‐nitrophenol, m‐nitrophenol, p‐nitrobenzoic acid, and nitrobenzene) can all cause sensitive cathodic peaks under the conditions, but their peak potentials and peak currents are different to some extent. Their peak currents and concentrations show linear relationships in concentration ranges with about 3 orders of magnitude. The detection limits are 8.0×10?9 M for p‐nitroaniline, 2.0×10?9 M for p‐nitrophenol, 5.0×10?9 M for o‐nitrophenol, 5.0×10?9 M for m‐nitrophenol, 2.0×10?8 M for p‐nitrobenzoic acid and 8.0×10?9 M for nitrobenzene respectively. The BMIMPF6‐SWNT/GCE is applied to the determination of NACs in lake water. 相似文献
164.
Two novel 3D coordination polymers {[Mn(aip)(DMF)]}n, CPO-9, and {[Mn3(Hatp)2(atp)2](H2O)2(DEF)4}n CPO-10 (aip = 5-aminoisophthalate, atp = 2-aminoterephthalate, DMF = dimethylformamide, DEF = diethylformamide) have been synthesized by solvothermal methods. Their properties have been studied by single-crystal X-ray diffraction, thermogravimetric analysis, high-temperature powder X-ray diffraction and magnetic susceptibility measurements. The crystal structure of CPO-9 is based on infinite chains of carboxylato-bridged five-coordinated Mn(II) ions that are crosslinked via the aip ligands to form a 3D structure. CPO-10 is based on linear trinuclear building units of carboxylato-bridged octahedral Mn(II) ions that are crosslinked by the atp ligands into a 3D structure. Both compounds have 1D channels that contain solvent molecules. The solvent accessible void volume for CPO-10 is 51.9% of the unit cell volume. For both compounds, however, the solvent molecules cannot be removed without the collapse of the structures into amorphous phases at 250 °C. The magnetic susceptibility measurements indicate antiferromagnetic couplings between the Mn(II) ions in both compounds. The magnetic data have been fitted using theoretical approaches. 相似文献
165.
K. Laihia A. Valkonen E. Kolehmainen R. Suontamo M. Nissinen V. Nikiforov S. Selivanov 《Journal of Molecular Structure》2005,754(1-3):77-84
The 1H and 13C NMR chemical shifts for six toxaphene congeners: 2-exo,3-endo,6-exo,8,9,10-hexachloro- (1), 2-exo,3-endo,5-exo,9,9,10,10-heptachloro- (2), 2-exo,3-endo,6-exo,8,9,10,10-heptachloro- (3), 2-exo,3-endo,5-exo,6-endo,8,9,10-heptachloro- (4), 2-exo,3-endo,5-exo,6-endo,8,9,9,10-octachlorobornane (5) and 2,5-endo,6-exo,8,9,9,10,10-octachloro-2-bornene (6) are reported. Their chemical shift assignments have been obtained by means of Pulsed Field Gradient (PFG) Double Quantum Filtered (DQF) 1H,1H correlation spectroscopy (COSY), PFG 1H,13C Heteronuclear Multiple Quantum Coherence (HMQC) and PFG 1H,13C Heteronuclear Multiple Bond Correlation (HMBC) experiments. A single crystal X-ray structural analysis was made for compounds 1, 3, 4 and 6. The prevalences of two octachlorobornene rotamers (6a,6b) were elucidated by ab initio MO method and single point DFT/GIAO calculations for 13C chemical shifts. Theoretical calculations proved that the single crystal structure of 6 corresponds its most stable conformer in solution. 相似文献
166.
The use of capillary electrophoresis (CE) with laser-induced fluorescence excited by ultraviolet (UV) lasers in the range 200–300 nm has been restricted by the available wavelengths and expense of UV lasers. The integration of a NeCu deep UV laser operating at 248.6 nm with a single channel CE system with post-column sheath flow detection allows detection limits for serotonin and tryptophan of 3.9×10-8 M and 4.5×10-8 M respectively. Single cell analysis of serotonergic metacerebral cells from the sea slug Aplysia californica yields a value of 800±85 fmol of serotonin in each cell soma. For the first time, serotonin is directly detected in electrically stimulated release from single metacerebral cell soma, with approximately 4% of the serotonin contained in the soma released from a semi-intact preparation with a 2 min electrical stimulation. 相似文献
167.
Woods M Zhang S Ebron VH Sherry AD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(19):4634-4640
The lanthanide(III) complexes of three tetraamide DOTA bearing pyridyl, phenolic and hydroxypyridyl substituents have been studied by NMR, luminescence and cyclic voltammetry. The relaxivity profiles of the gadolinium complexes of the pyridyl and phenolic ligands were flat and essentially the same between pH 2 and 8. The hydroxypyridyl ligand, however, exhibited two regions of enhanced relaxivity. The small relaxivity enhancement (25 %) at lower pH (pH 2-4) has been attributed to an increase in the prototropic exchange of the coordinated water molecule while the slightly larger enhancement (84 %) at higher pH (pH 6-9) reflects deprotonation of the ligand amide protons. Deprotonation of the amides results in the formation of an intramolecular acid-base pair interaction with the phenolic protons and this, in turn, causes a highly organized second hydration sphere to come into effect, thereby increasing the relaxivity. The water relaxivity of the Gd(3+)-hydroxypyridyl complex is further enhanced upon binding to serum albumin. 相似文献
168.
169.
170.
Isaac Zigelboim Daniel Offen Eldad Melamed Hana Panet Moshe Rehavi Yoram Cohen 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):323-329
Although magnetic resonance imaging (MRI) is one of the most important imaging modalities of the central nervous system (CNS),
one of the main drawbacks of MRI is its limited specificity. This can potentially be partially alleviated by target-specific
contrast agents. In the present paper we describe a simple high yield synthesis of two such gadolinium-based spiperone targeted
MRI contrast agents, 1a and 1b. The R1 relaxivities of 1a and 1b were evaluated and found to be 5.94 and 8.31 mM−1 s−1, respectively at 9.4T, while their R2 relaxivities at the same magnetic field were found to be 18.05 and 22.60 mM−1 s−1, respectively. In addition and very importantly compound 1a, which is a gadolinium-based, spiperone-targeted MRI contrast agent, was found to preserve some of the spiperone affinity
toward the dopamine D2 receptor. Compounds 1a and 1b thus represent potential agents for in vitro dopamine receptor imaging using MRI in experimental models.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献