Project description:In the crystal structure of the title compound, C(15)H(11)FN(2), the pyrrole ring makes dihedral angles of 33.19 (9) and 36.33 (10)° with the pyridine and 4-fluoro-phenyl rings, respectively. The pyridine ring makes a dihedral angle of 46.59 (9)° with the 4-fluoro-phenyl ring. In the crystal structure, an N-H⋯N hydrogen bond joins the mol-ecules into chains.
Project description:In the title compound, [Zn(C(7)H(5)O(2))(2)(C(10)H(10)N(2))(2)], the Zn(II) ion, located on a twofold axis, is coordinated by two N atoms from two 3-(pyrrol-1-ylmeth-yl)pyridine ligands and two O atoms from two benzoate ligands in a distorted tetra-hedral geometry. The pyridine and the pyrrole rings are nearly perpendicular to each other, making a dihedral angle of 84.83 (7)°.
Project description:The piperidine ring of the title compound, C(16)H(15)N(5), adopts a chair conformation. The pyridine ring is essentially planar, with a maximum deviation of 0.035 (3) Å. The pyrrole and pyridine rings are almost coplanar, forming a dihedral angle of 3.48 (14)°. In the crystal, no classical hydrogen bonds were found. In the crystal, the molecules are linked by aromatic π-π stacking [centroid-centroid separations = 3.4984 (16) and 3.9641 (15) Å between pyrrole and pyridine rings and between pyridine rings, respectively].
Project description:In the title compound, C(15)H(13)N(5)O, the morpholine ring adopts a chair conformation. The dihedral angle between the pyrrole ring and the pyridine ring is 28.93 (14)°. In the crystal, the molecules are linked by C-H⋯O hydrogen bonds occur, and aromatic weak π-π stacking [centroid-centroid separation = 4.178 (2) Å] and C-H⋯π inter-actions consolidate the packing.
Project description:A new squaraine based chemosensor TSQ was developed for colorimetric detection of Fe3+ ions. A thymine moiety in TSQ was constructed to act as an ion acceptor. The sensor displayed an instant colorimetric response specific to Fe3+ over the other metal ions in 20% AcOH-H2O solution. The limit of detection was much lower than that of the environmental protection agency guideline (5.37 μM) in drinking water. A 1 : 1 binding between TSQ and Fe3+ ion was evidenced by Job's plot measurement, ESI-MS and Fourier transform infrared (IR) measurements. Moreover, the proposed sensing mechanism of the receptor towards Fe3+ was strongly supported by DFT calculation. Finally, the sensor has proven to be suitable in real sample applications.
Project description:A novel pyranopyrazole-based Schiff base PPS has been synthesized via a condensation reaction between aldehyde and hydrazide derivatives of pyranopyrazole. The probe acted as a selective and sensitive chemosensor for the colorimetric detection of arginine under aqueous conditions with a detection limit of 1.8 × 10-5 M. The 1 : 1 binding stoichiometry was established using various UV-vis spectroscopic methods. A plausible binding mechanism of PPS towards arginine was established via 1H NMR titration techniques and the results were further validated using DFT studies. Moreover, PPS provided a reasonable response for arginine in dietary supplements and human blood plasma which demonstrates its potential application in real sample analysis as well.
Project description:In the title compound, C(12)H(12)N(4)O, the pyridine and pyrrole rings are inclined at an angle of 29.22 (8)° and an intra-molecular C-H⋯N inter-action geneates an S(6) ring. In the crystal, mol-ecules are linked by N-H⋯N hydrogen bonds, forming (010) C(7) chains. The chains are cross-linked by weak C-H⋯O inter-actions, which generate R(2) (2)(18) ring motifs within an infinite sheet. Finally, two C-H⋯π inter-actions are present, where the C-H groups are from the pyridine ring and π is the pyrrole ring.
Project description:Due to the great threat posed by excessive nitrite in food and drinking water to human health, it calls for developing reliable, convenient, and low-cost methods for nitrite detection. Herein, we string nanozyme catalysis and diazotization together and develop a ratiometric colorimetric approach for sensing nitrite in food. First, hollow MnFeO (a mixture of Mn and Fe oxides with different oxidation states) derived from a Mn-Fe Prussian blue analogue is explored as an oxidase mimic with high efficiency in catalyzing the colorless 3,3',5,5'-tetramethylbenzidine (TMB) oxidation to blue TMBox, presenting a notable signal at 652 nm. Then, nitrite is able to trigger the diazotization of the product TMBox, not only decreasing the signal at 652 nm but also producing a new signal at 445 nm. Thus, the analyte-induced reverse changes of the two signals enable us to establish a ratiometric colorimetric assay for nitrite analysis. According to the above strategy, facile determination of nitrite in the range of 3.3-133.3 μM with good specificity was realized, providing a detection limit down to 0.2 μM. Compared with conventional single-signal analysis, our dual-signal ratiometric colorimetric mode was demonstrated to offer higher sensitivity, a lower detection limit, and better anti-interference ability against external detection environments. Practical applications of the approach in examining nitrite in food matrices were also verified.
Project description:D-amino acids are of biological significance yet are not clearly understood due to the lack of powerful analytical tools for their identification. Thus, the specific detection of a single enantiomer of a particular amino acid remains a great challenge due to their structural similarity. Here, we report a strategy to incorporate multiple reaction sites on a chiral 1,1'-bi-2,2'-naphthol-based fluorescent probe. It can respond specifically to D-arginine, while producing no response when in contact with all other amino acids. The probe can report arginine's concentration, and enantiomeric configuration and colorimetric studies enable its qualitative determination.
Project description:Bisulfite and sulfite (HSO3 -/SO3 2-) are not only widely used toxic chemicals but also active anions with important biological functions. Hence, the development of new detection methods for HSO3 -/SO3 2- is important for environmental security and human health. In this paper, we report a symmetrical hemicyanine for the detection of HSO3 -/SO3 2-, SHC, which is constructed with p-diphthalaldehyde with trimethylbenzoindolium via condensation. The red fluorescent probe can fast respond to HSO3 -/SO3 2- (<30 s) to give cyan fluorescence, and its sensing process is twice nucleophilic additions, which were observed from fluorescence response, initial ratiometric change, and subsequent turn-on increment; especially in a low-concentration level, the ratiometric fluorescence measurement can eliminate environmental interference. This probe can achieve a quantitative detection of HSO3 -/SO3 2- in a wide concentration range. Furthermore, the probe SHC is a mitochondria-specific probe for ratiometric fluorescent detection of HSO3 -/SO3 2- in living cells.