Development of aryl-containing dipyrrolyldiketone difluoroboron complexes(BONEPYs):Tune the hydrogen bond o-C—H…F for fluoride recognition

Dipyrrolyldiketone difluoroboron complexes(BONEPYs)were synthesized by condensation of the corresponding pyrroles and malonyl chloride followed by treatment with BF3·OEt2.The aryl-substituted pyrrole is introduced to form a cyclic system in order to investigate anion binding studies.In BONEPYs 1-3 the o-H of the aryl group forms hydrogen bonding with F to give a more table complex.In contrast,the intramolecular hydrogen-bonded BONEPY endo-4 is more stable than its exo isomer.While adding F,the hydrogen bonds must be broken first to give 4·(3)F.Owing to the electron-rich group(-OMe),the o-H of the phenyl group can hardly interact with F via hydrogen bonding to give the less stable complex4-(5)F.The energy diffe rences between the different conformations were calculated using DFT methods,which is consistent to the experimental observations.     

A cation trap for anodic stripping voltammetry: NH3–plasma treated carbon nanotubes for adsorption and detection of metal ions

NH₃–plasma treated multi-walled carbon nanotubes (pn-MWCNTs) with cation traps for the detection of ultratrace quantities of Zn(II), Cd(II), Cu(II), and Hg(II) using square wave anodic stripping voltammetry (SWASV) is described. The pn-MWCNTs use their adsorption performance to enhance the sensitivity. It is found that under optimized conditions Zn(II), Cd(II), Cu(II) and Hg(II) were individually detected at potentials of −1.16, −0.78, −0.268 and 0.108 V, respectively. The detection limit (3σ method) of 0.314, 0.0272, 0.2263, and 0.1439 nM toward Zn(II), Cd(II), Cu(II), and Hg(II) is achievable, respectively. No interference could be seen during the simultaneous detection of Zn(II), Cd(II), Cu(II), and Hg(II). The pn-MWCNTs exhibit excellent selectivity owing to the different ability of adsorption. A study of the ability of pn-MWCNTs in practical application is carried out using a sample of water collected from Dongpu Reservoir in Hefei City, Anhui, China. It is found that the results were favorable when compared against inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis.     

Benzisoxazole core and benzoxazolopyrrolidine via HDDA-derived benzyne with PTIO/DMPO

A novel method for HDDA-derived benzyne trapped by nitrone was developed. This research described a simple and efficient pathway for the synthesis of benzisoxazoles from arynes and PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl), C?C and C?O bonds were formed in a single step without catalyst under mild conditions. The unexpected cleavage of C?N bond contributed to the formation of isoxazole ring, as indicated by DFT studies. Furthermore, we obtained the structure of benzoxazolopyrrolidine when the trapping agent is DMPO (5,5-dimethyl-1-pyrroline N-oxide).