Ring-closure reactions. 19. Kinetics of formation of benzo-crown ethers by intramolecular nucleophilic substitution. A comparison between polyoxyethylene and polymethylene chains
A Novel Crown Ether Generation Containing Different Heteroaromatic Cations: Synthesis, Characterization, Solid-Phase <sup>13</sup>C NMR, X-ray Crystal Structure, and Selective Amino Acid Recognition
作者:Abolghasem Moghimi、Majid Faal Rastegar、Mehdi Ghandi、Masoud Taghizadeh、Abdollah Yari、Mojtaba Shamsipur、Glenn P. A. Yap、Hamid Rahbarnoohi
DOI:10.1021/jo010869f
日期:2002.4.1
The synthesis and structural characterization of a novel generation of crownethers, 3, 5 and 6 containing pyrilium, thiopyrilium, and pyridinium subunits, respectively, are reported. The crownether unit is potentially capable of forming host-guest complexes with inorganic and organic cations, while the heteroaromatic cationic unit is suitable to bind with anions. A variety of physicochemical methods
New ferrocenyl naphthoquinone fused crown ether chemosensors: Highly selective, kinetically and regio controlled colorimetric, beryllium ion recognition
addition of Be2+ ion into the solution of sensors Fc–cnq–1a and Fc–cnq–1b. However, no spectral changes were observed for the other metalcations used for testing at the same conditions, indicating that the sensors can selectively detect Be2+ among the studied metalions even at higher temperatures. The spectral change in the absorption spectra of the sensors upon addition of Be2+ ion corresponds to
Sidewall functionalization of single-walled carbon nanotubes (SWCNTs) by the covalent addition of 4-benzo-9-crown-3 ether diazonium salt has been described. The covalent grafting of crown ether has led to a considerable increase in the solubility of SWCNTs in both organic and aquatic solvents such as ethanol, dimethyl sulfoxide, dimethylformamide and water. The highest solubility was attained in DMF and DMSO. The covalently bonded 4-benzo-9-crown-3 ether allowed the hosting of Li+. The covalent grafting of crown ether [4-(benzo-9-crown-3)] to SWCNT was identified and confirmed by infrared spectroscopy, transmission electron microscopy, UV/Vis and thermogravimetric analysis methods.
A comparative study of the stereochemistry of 4-acetyl-, formyl- and carboxy-benzo-9-crown-3 ether via X-ray crystallography and solid state and solution NMR spectroscopy
作者:G.W. Buchanan、M.F. Rastegar、G.P.A. Yap
DOI:10.1016/s0022-2860(00)00775-4
日期:2001.4
Abstract The X-ray crystal structures for the title molecules show remarkably similar geometries in the crown ether regions compared to benzo-9-crown-3 ether itself. Solid phase 13C NMR chemical shift differences of ca. 8.5 ppm are observed between the two aryl–O–C∗ carbons and are explained using results of ab initio calculations previously performed on anisole. Chemical shift assignments have been
摘要 标题分子的 X 射线晶体结构在冠醚区域显示出与苯并-9-冠-3 醚本身非常相似的几何形状。固相 13C NMR 化学位移差异约为 在两个芳基-O-C* 碳之间观察到 8.5 ppm,并使用先前对苯甲醚进行的 ab initio 计算结果进行解释。化学位移分配已通过使用选择性氘化衍生物进行了验证。
A novel crown ether generation containing the pyrilium heteroaromatic cation Synthesis, characterization, and solid-phase <sup>13</sup>C NMR
作者:Abolghasem Moghimi、Majid Faal Rastegar、Mehdi Ghandi
DOI:10.1139/v04-144
日期:2004.12.1
The synthesis and structural characterization of two members, 5 and 6, of a novel generation of crownetherscontaining the pyrilium cation are reported. These two compounds containtwo and three benzo-9-crown-3 (B9C3) units, respectively, connected to the 2 and 6 or 2, 4, and 6 positions of a central pyrilium cation. The crownethers 5 and 6 were obtained from the condensation reaction of appropriate