Five new chiral macrocycles, 3a-e, have been prepared by the acylation cyclization of chiral diamine dihydrobromide intermediates 2a-c with 2,6-pyridinedicarbonyl dichloride in highly diluted solution at room temperature. The chiral diesters 1a-c needed for the preparation of the macrocycles were obtained from condensation of corresponding N-(Z)-L-amino acids and 2,6-bishydroxymethyl pyridine in the presence of DCC and DMAP. The enantiomeric recognition of chiral macrocycles 3a-e for D- and L-amino acid methyl ester hydrochlorides has been characterized by fluorescence spectra, which indicate that some of them exhibited significant chiral recognition for the enantiomers of D- and L-amino acid methyl ester hydrochlorides. The stoichiometry and binding constants of 3a-L-Am(2) and 3c-L-Am(2) complexes have been determined. An X-ray analysis of the chiral macrocycle 3b show that the chiral ligand is rather rigid and strained.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract The synthesis of chiral C 2-symmetric substituted bisoxazoline ligands containing naphthalene group were investigated. Ethyl 2,3-naphthylene-dicarboxylate reacted with amino alcohols and the resulting amides were treated with SOCl2 and then reacted with Et3N in toluene to afford the desired bisoxazolines. 2,3-Naphthylenedicarbonitrile reacted with amino alcohol give N- (1′-phenyl-2′-hydroxyethyl)-2,3-naphthylenedicarboximide 1. The 2,3-naphthylenedicarboxylic acid reacted with thionyl chloride give the 2,3-Naphthalenedicarboxylic acid cyclic anhydride rather than corresponding 2,3-naphthalenedicarboxylic acid dichloride, the former reacted with amino alcohol also give compound 1. The later two strategies cannot give the target bisoxazoline.
A new magnetic nanoadsorbent (Fe3O4@SiO2@PAA-SO3H) was synthesized by reflux precipitation polymerization and its performance in removing of Pb(II) and Cu(II) from water was examined. This presented an optimal adsorption capacity for Pb(II) and Cu(II) of 182.5 mg/g and 250.7 mg/g, respectively, at pH 6.0. The fitting of adsorption isotherms and kinetics indicate that the adsorption is chemical and monolayer. Simultaneously, the magnetic nanoadsorbent has high selectivity for Pb(II) and Cu(II) in the presence of other anions and cations. The adsorption-desorption cycles show that the nanoadsorbent presents advanced recycling and is highly water-stable. The adsorption active sites were further analyzed using electrostatic potential (ESP) and average local ionization energy (ALIE) by density functional theory (DFT), revealing that the Pb(II) and Cu(II) binding was attributed to the oxygen active sites locating in the repeating unit of Fe3O4@SiO2@PAA-SO3H. As the Fe3O4@SiO2@PAA-SO3H adsorbent is a hierarchical, highly water-dispersible and biocompatible adsorbent, it is a potential new treatment option for wastewater.
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