2,859 publications from this institution
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.
Graphene oxide (GO) sustains with some natural decay of its epoxy sites. The time-duration needed for autotermination of this decay process is still unknown. We present the duration of ending GO’s structural deformation and proton–electron conductive inflection. The chemical structure (CS), proton conductivity (PC), and electron conductivity (EC) of GO synthesized from Hummers' method and preserved for six years at 1 atm pressure and 25 °C (ambient condition) have been studied at the 0th, 2nd, 4th, and 6th years of the synthesis. The physico-chemical changes were pronounced within 0–2 years. The changes continued but reduced in 2–4 years. Finally, the processes almost terminated within 4–6 years. The PC values significantly fall in the 2nd year, continued to some lower extent in the 4th year, and remained almost unchanged in the 6th year. The EC increased significantly in the 2nd year, moderately in the 4th year, and remained almost unchanged in the 6th year. The chemical structures analyzed by X-ray photoelectron spectroscopy (XPS) show that the amount of epoxy groups in freshly prepared GO gradually reduces with time up to the 4th year. Slight increases in the −OH and −COOH contents indicate the conversion of some epoxy groups into these functional sites. Raman spectra show that the C═C domain of freshly prepared GO increases gradually between 0 and 4 years and suffer insignificant changes in 4–6 years. Some shifting in the powder X-ray diffraction (PXRD) pattern indicates time-dependent changes of the interlayer distance (ID) of GO. GO’s chemical structure clearly suffers from some spontaneous and irreversible intraconversion of functional groups, which directly affects its conductive behavior.
The electrochemical reduction mechanism of 4′-nitrotricyanovinylhydrazone in DMF–B-R buffer to the corresponding [(4-hydroxyamino)phenyl]methamine <italic>via</italic> 2H<sup>+</sup>/2e<sup>−</sup> reduction of (<italic>E</italic>)-<italic>N</italic>-(1-(4-hydroxyamine)phenylethylidene)methamine is proposed.
Two independent mol-ecules, A and B, comprise the asymmetric unit of the title compound, C(21)H(18)N(2)OS, with the difference in the angle of orientation between the naphthalene ring system and the mean plane of the cyclo-heptyl ring [16.13 (1) in A and 11.48 (5)° in B], being evident. The cyclo-heptyl ring adopts a distorted chair conformation in each mol-ecule with r.m.s. deviations of 0.2345 (4) (A) and 0.2302 (4) Å (B). Intra-molecular O-H⋯N hydrogen bonding generates planar six-membered S(6) loops with r.m.s. deviations of 0.0099 (1) (A) and 0.0286 (1) Å (B).
In the title compound, C(14)H(10)F(3)N(3)O(3)S, there are significant twists in the mol-ecule, as seen in the values of the dihedral angles between the pyrazole ring and each of the furan [31.1 (2)°] and benzene rings [55.58 (10)°]. The amino N atom occupies a position almost normal to the benzene ring [N-S-C(ar)-C(ar) (ar = aromatic) torsion angle = 83.70 (19)°]. One amino H atom forms a hydrogen bond to the tricoordinate pyrazole N atom and the other inter-acts with a sulfonamide O atom, forming a supra-molecular chain along [010]. The chains are consolidated into a supra-molecular layers via C-H⋯O inter-actions involving the second sulfonamide O atom; layers stack along [10-1]. The furan ring was found to be disordered over two diagonally opposite orientations of equal occupancy.
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.
In this study, a novel <i>in situ</i> choline sensor was assembled by attaching the binary Mn<sub>2</sub>O<sub>3</sub>/NiO nanoparticles (NPs) onto a glassy carbon electrode (GCE). Initially, Mn<sub>2</sub>O<sub>3</sub>/NiO NPs were synthesized <i>via</i> a wet-chemical process and fully characterized <i>via</i> XRD, XPS, FESEM, EDS, FTIR and UV-Vis methods. The analytical performances of the choline sensor were evaluated by an electrochemical method in the phosphate buffer phase. The estimated linear dynamic range (LDR) was found to be 0.1 nM to 0.1 mM. The other analytical performances of the choline sensor, such as sensitivity (16.4557 μA μM<sup>-1</sup> cm<sup>-2</sup>) and detection limit (5.77 ± 0.29 pM), were also calculated very carefully from the calibration plot. Overall, the choline sensor exhibited a reliable reproducibility, <i>in situ</i> validity, selectivity, interference effect, stability, and intra-day and inter-day performances with high accuracy in a short response time. Moreover, the probe was successfully applied to detect choline in real human, mouse and rabbit serum. This fabrication route would be a novel approach for the detection of selective biochemical sensor in the healthcare and biomedical fields.
