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There is an urgent need to develop in situ sensors that monitor the continued release of H2S from biological systems to understand H2S-related pathology and pharmacology. For this purpose, we have developed a molybdenum disulfide supported double-layered zinc cobaltite modified carbon cloth electrode (MoS2–ZnCo2O4–ZnCo2O4) based electrocatalytic sensor. The results of our study suggest that the MoS2–ZnCo2O4–ZnCo2O4 electrode has excellent electrocatalytic ability to oxidize H2S at physiological pH, in a minimized overpotential (+0.20 vs. Ag/AgCl) with an amplified current signal. MoS2 grown on double-layered ZnCo2O4 showed relatively better surface properties and electrochemical properties than MoS2 grown on single-layered ZnCo2O4. The sensor delivered excellent analytical parameters, such as low detection limit (5 nM), wide linear range (10 nM–1000 μM), appreciable stability (94.3%) and high selectivity (2.5-fold). The practicality of the method was tested in several major biological fluids. The electrode monitors the dynamics of bacterial H2S in real-time for up to 5 h with good cell viability. Our research shows that MoS2–ZnCo2O4–ZnCo2O4/carbon cloth is a robust and sensitive electrode to understand how bacteria seek to adjust their defense strategies under exogenously induced stress conditions. [ABSTRACT FROM AUTHOR]

A robust real-time quantification method is essential to understand the physiological roles of endogenous H2O2 in biological systems. For this purpose, we described a binary transition-metal oxide (TMO)-based nanointerface, i.e., spinal zinc cobaltite/cobalt oxide ternary nanoarrays (ZnCo2O4/Co3 O4) on a Cu foam (CF). The ZnCo2O4/Co3O 4/CF facilitates H2O2 reduction at a minimized overpotential (-0.10 V vs Ag/AgCl). which is several millivolts away from the voltammetric regions of common biological and oxygen interferences, making the electrode highly selective in the presence of 5-fold excess concentrations of biological species. In the presence of ZnCo2O4, the electrocatalytic capability of Co3O4 has increased significantly by enlarging the electrochemical active area of the electrode (0.538 cm²). A substantial improvement in the stability (97.24%) and reproducibility (relative standard deviation = 3.14%) are attained because the direct growth of nanomaterials is generated on CF in close proximity with the electrode surface and strengthens the affinity. The modified electrode endows ultrasensitivity (detection limit = 1 nM) and quantifies the amount of H2O2 released from mammalian cells (8.7 x 10-14 mol). Binary TMOs hold promise in tailoring a reliable H2O2-detecting interface for real-time, in vivo applications. [ABSTRACT FROM AUTHOR]

Carbon-based fluorescent nanoparticles have attracted a lot of attention in the field of bioimaging as a result of their excellent emission properties along with their low toxicity. Fluorescent carbogenic nanoparticles (CNPs) were synthesized by a one-pot microwave pyrolysis technique by using Triton X-100 as a carbon source. The CNPs are spherical in shape with an average diameter of 5.5 nm, as characterized by transmission electron microscopy and atomic force microscopy. The as-synthesized CNPs showed strong blue emission under UV illumination, excitation-dependent emission properties, and chemical stability under different pH conditions. The graphitic nature of the CNPs was studied by using Raman and X-ray photoelectron spectroscopy. Moreover, the toxicity of these particles was studied through an MTT assay, which showed no noticeable toxicity. The results suggest that the CNPs can be used as effective fluorescent probes for cellular imaging applications. [ABSTRACT FROM AUTHOR]

In the title complex, C5H16N22+·2C6H2N3O7−, the two picrate anions lie almost parallel to each other and have possible π–π inter­actions between them. One of the anions is involved in limited N—H⋯O bonds, whereas the other engages in extensive N—H⋯O and C—H⋯O hydrogen bonds. Tilting of one of the ortho nitro groups in the picrate anion is influenced by the N—H⋯O hydrogen bond. The dimethyl­aminopropyl­ammonium and picrate ions are linked through N—H⋯O and C—H⋯O hydrogen bonds, forming chains along the crystallographic b axis. The anions form near-helical columns along the b axis owing to the presence of a 21 screw and are separated by nearly linear cationic chains. [ABSTRACT FROM AUTHOR]

The title mol­ecular complex, C25H25BrF3N4+·C6H2N3O7−, crystallizes with two pairs of cations and anions in the asymmetric unit. While the orientations of the two cations are nearly parallel to one another, this is not so for the anions. The imidazonaphthyridine moiety is planar and the methyl­piperidine group is approximately perpendicular to it and adopts an ideal chair conformation. The planes of the bromo­phen­yl rings deviate from the planes of the imidazonaphthyridine moieties by 30.2 (2) and 22.6 (3)° in the two cations, making a marked difference in the overall conformation of the cations. The N—H⋯N hydrogen bond forms an intra­molecular ring pattern S(7) in both cations. The anions and cations are connected through N—H⋯O, C—H⋯O and C—H⋯F hydrogen bonds. [ABSTRACT FROM AUTHOR]

The title salt, C6H16N+·C6H2N3O7−, crystallizes with two pairs of cations and anions in the asymmetric unit. Anions A and B are stacked alternately in the (020) plane to form anionic columns having an ABABAB... sequence, with possible π–π inter­actions between them. The cationic columns surround these columns in an almost hexa­gonal fashion, with each column of the same type of cation, A or B. The anions and cations are connected through lone N—H⋯O and by other C—H⋯O hydrogen bonds. N—H⋯O and C—H⋯O hydrogen bonds involving A-and B- type ions form a cyclic pattern with a graph-set descriptor R22(10). [ABSTRACT FROM AUTHOR]

In the title salt, C21H23N4+·C6H2N3O7−·H2O, the dimethyl­ammonio­methyl side chain is oriented nearly perpendicular to the imidazonaphthyridine moiety, which is nearly planar. In the crystal structure, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link two cations, two anions and two water mol­ecules into clusters, which further inter­act via weak C—H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the title salt, C2H8N+·C6H2N3O7−, there is complete transfer of the OH proton from picric acid to the amine. The picrate anions lie almost parallel to the monoclinic (101) plane and are connected by O⋯O short contacts. The ethyl­aminium and picrate ions are linked through N—H⋯O and C—H⋯O hydrogen bonds along the crystallographic b axis. In the picrate anion, tilting of the para-nitro group is a consequence of C—H⋯O hydrogen bonding between the ions. [ABSTRACT FROM AUTHOR]

In 3-methyl­anilinium picrate (3-MAP), C7H10N+·C6H2N3O7−, one of the nitro groups in the picrate ion is rotationally disordered with site occupancy factors of 0.80 and 0.20. The expected proton transfer took place between picric acid and 3-methyl­aniline, and the amine group is hydrogen bonded to two of the phenolate O atoms. The ortho-nitro groups deviate greatly from the benzene plane of the picrate ion, facilitating hydrogen-bond formation. While the cations are stacked as columns along the [001] direction, the anions are stacked in an offset fashion. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title salt, C6H14N+·C6H2N3O7−, picrate anions lie parallel to one another with a relative orientation of nearly 120°. The protonated N atom of the cation makes one linear and two bifurcated hydrogen bonds with three neighbouring picrate ions. The centrosymmetrically related anions and cations form hydrogen-bonded graph-set motifs of R42(8) and R44(12) alternately along the [010] direction. [ABSTRACT FROM AUTHOR]

There is an urgent need to develop in situ sensors that monitor the continued release of H2S from biological systems to understand H2S-related pathology and pharmacology. For this purpose, we have developed a molybdenum disulfide supported double-layered zinc cobaltite modified carbon cloth electrode (MoS2-ZnCo2O4-ZnCo2O4) based electrocatalytic sensor. The results of our study suggest that the MoS2-ZnCo2O4-ZnCo2O4 electrode has excellent electrocatalytic ability to oxidize H2S at physiological pH, in a minimized overpotential (+0.20 vs. Ag/AgCl) with an amplified current signal. MoS2 grown on double-layered ZnCo2O4 showed relatively better surface properties and electrochemical properties than MoS2 grown on single-layered ZnCo2O4. The sensor delivered excellent analytical parameters, such as low detection limit (5 nM), wide linear range (10 nM-1000 μM), appreciable stability (94.3%) and high selectivity (2.5-fold). The practicality of the method was tested in several major biological fluids. The electrode monitors the dynamics of bacterial H2S in real-time for up to 5 h with good cell viability. Our research shows that MoS2-ZnCo2O4-ZnCo2O4/carbon cloth is a robust and sensitive electrode to understand how bacteria seek to adjust their defense strategies under exogenously induced stress conditions.