A highly selective ratiometric fluorescent probe for H2S based on new heterocyclic ring formation and detection in live cells

A 3-indolylacrylate derivative, 3-IA, prepared by connecting an ethyl acrylate in 3-position of indole has been synthesised and characterised. Ethyl acrylate moiety acts as the Michael acceptor towards H₂S, and the resultant addition product then participates in intramolecular cyclisation with the ester group at 2-position to form another new heterocyclic ring. Blue fluorescence of 3-IA turned into green in presence of H₂S, leading to ratiometric behaviour of the fluorescent sensor with large stokes shift of 55 nm. Probe 3-IA has excellent selectivity towards H₂S over other biothiols and other competing anions. Density function theory/time-dependent density function theory calculations were carried out to validate the reaction mechanism and the electronic properties of 3-IA. Importantly, the ratiometric probe 3-IA shows great promise in H₂S detection by simple visual fluorescent inspection in filter paper-based protocol. The probe shows its excellent ability to detect H₂S in different natural water samples. Furthermore, we have employed our probe to detect H₂S for ratiometric imaging in live Vero cell.     

Near‐Unity Photoluminescence Quantum Efficiency for All CsPbX3 (X=Cl,Br, and I) Perovskite Nanocrystals: A Generic Synthesis Approach

In a generic synthesis approach, all three CsPbX₃ (X=Cl, Br and I) perovskite nanocrystals having near unity quantum yields is reported. This has been achieved by injecting the desired amount of preformed alkylammonium halide salts which acted as a dual source providing halide ions and the capping agent to an equimolar amount of non‐halide Pb and Cs precursors in a reaction flask at an optimized reaction temperature. The composition sensitivity of Pb to Cs ratio, high temperature reaction, and injection of ammonium halide remained the key parameters for obtaining the high quantum yields. Details of the reaction process, use of different reagents and setting up the reaction parameters are reported.     

Stability indicating liquid chromatographic method for simultaneous quantification of betamethasone valerate and tazarotene in in vitro and ex vivo studies of complex nanoformulation

Low‐potency corticosteroid betamethasone valerate and vitamin‐A tazarotene are used in combination for effective treatment of psoriasis. There is no robust high‐performance liquid chromatography analytical technique available for simultaneous estimation of betamethasone valerate and tazarotene in conventional and nanocarriers based formulations. A simple, accurate, robust isocratic high‐performance liquid chromatography method was developed for simultaneous estimation of betamethasone valerate and tazarotene in topical pharmaceutical formulations. The developed method was validated as per the regulatory guidelines. The validated method was linear over the concentration range of 150–6000 ng/mL (r² > 0.999) at 239 nm wavelength. Limits of detection and quantification of two analytes were 50 and 150 ng/mL, respectively. The %relative standard deviation for intraday and interday precision was less than 2%. The method was also evaluated in the presence of forced degradation conditions. The developed method was successfully applied for in vitro and ex vivo drug release studies of in‐house designed nanoformulations.     

Recent Advances in BODIPY Compounds: Synthetic Methods,Optical and Nonlinear Optical Properties,and Their Medical Applications

Organoboron compounds are attracting immense research interest due to their wide range of applications. Particularly, low-coordinate organoboron complexes are receiving more attention due to their improbable optical and nonlinear optical properties, which makes them better candidates for medical applications. In this review, we summarize the various synthetic methods including multicomponent reactions, microwave-assisted and traditional pathways of organoboron complexes, and their optical and nonlinear properties. This review also includes the usage of organoboron complexes in various fields including biomedical applications.     

Red-Emitting Delayed Fluorescence and Room Temperature Phosphorescence from Core-Substituted Naphthalene Diimides

Unprecedented ambient triplet-mediated emission in core-substituted naphthalene diimide (cNDI) derivatives is unveiled via delayed fluorescence and room temperature phosphorescence. Carbazole core-substituted cNDIs, with a donor–acceptor design, showed deep-red triplet emission in solution processable films with high quantum yield. This study, with detailed theoretical calculations and time-resolved emission experiments, enables new design insights into the triplet harvesting of cNDIs; an important family of molecules which has been, otherwise, extensively been investigated for its n-type electronic character and tunable singlet fluorescence.     

One-Pot Sequential Kumada–Tamao–Corriu Couplings of (Hetero)Aryl Polyhalides in the Presence of Grignard-Sensitive Functional Groups Using Pd-PEPPSI-IPentCl

We report a general and rapid chemoselective Kumada–Tamao–Corriu (KTC) cross-coupling of aryl bromides in the presence of chlorides or triflates with functionalized Grignard reagents at 0 °C in 15 min by using Pd-PEPPSI-IPent^Cl ( C4 ). Nucleophiles and electrophiles (or both) can contain Grignard-sensitive functional groups (-CN, -COOR, etc.). Control experiments together with DFT calculations suggest that transmetallation is rate limiting for the selective cross-coupling of Br in the presence of Cl/OTf with functionalized Grignard reagents. One-pot sequential KTC/KTC cross-couplings with bromo–chloro arenes have been demonstrated for the first time. We also report the one-pot sequential KTC/Negishi cross-couplings using C4 showcasing the versatility of this methodology.     

A facile green synthesis of silver nanoparticle-decorated hydroxyapatite for efficient catalytic activity towards 4-nitrophenol reduction

Research on Chemical Intermediates - Silver nanoparticles (AgNPs) were gradually grown on a hydroxyapatite surface via a green self-reducing approach. Hydroxyapatite (HAP) was functionalized by...     

Synthesis,reactivity, in vitro boron neutron capture therapy assay,and molecular docking of fluorocyclocarboxyboranylamine

The one-pot reaction of Me₃NBH₂CN with Et₃O⁺BF₄⁻ followed by addition of BF₃·Et₂O and water produces a trimethylamine derivative of fluorocyclocarboxyboranylamine, Me₃NBH₂C(O₂BF₂NH₂) ( 1 ) in 36.0% yield. Compound 1 undergoes exchange reaction between the exo-Me₃N moiety and piperidine or pyridine to produce the corresponding piperidine-substituted fluorocyclocarboxyboranylamine ( 2 ) or pyridine-substituted fluorocyclocarboxyboranylamine ( 3 ) in 51.2% or 42.4% yields, respectively. The new compounds were characterized by ¹H, ¹³C, ¹¹B, and ¹⁹F nuclear magnetic resonance spectroscopy; Fourier-transform infrared spectroscopy; and elemental analyses and the crystal structure of 1 was determined to confirm its molecular geometry. The in vitro killing effects of 1 , along with its toxicity measurements and molecular docking interactions with matrix metalloproteinases showed a potential promise of such species as both boron neutron capture therapy and boron neutron capture synovectomy agents in the treatment of tumors and rheumatoid arthritis, respectively, in the presence of slow neutrons.     

Photodissolution of ferrihydrite in the presence of oxalic acid: an in situ ATR-FTIR/DFT study

The photodissolution of the iron oxyhydroxide, ferrihydrite, in the presence of oxalic acid was investigated with vibrational spectroscopy, density functional theory (DFT) calculations, and batch geochemical techniques that determined the composition of the solution phase during the dissolution process. Specifically, in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR- FTIR) was used to determine the structure of the adsorbed layer during the dissolution process at a solution pH of 4.5. DFT based computations were used to interpret the vibrational data associated with the surface monolayer in order to help determine the structure of the adsorbed complexes. Results showed that at pH 4.5, oxalate adsorbed on ferrihydrite adopted a mononuclear bidentate (MNBD) binding geometry. Photodissolution at pH 4.5 exhibited an induction period where the rate of Fe(II) release was limited by a low concentration of adsorbed oxalate due to the site-blocking of carbonate that was intrinsic to the surface of the ferrihydrite starting material. Oxalate displaced this initial carbonate over time, and the dissolution rate showed a corresponding increase. Irradiation of oxalate/ferrihydrite at pH 4.5 also ultimately led to the appearance of carbonate reaction product (distinct from carbonate intrinsic to the starting material) on the surface.     

Application of cycloaddition reactions to the syntheses of novel boron compounds

This review covers the application of cycloaddition reactions in forming the boron-containing compounds such as symmetric star-shaped boron-enriched dendritic molecules, nano-structured boron materials and aromatic boronic esters. The resulting boron compounds are potentially important reagents for both materials science and medical applications such as in boron neutron capture therapy (BNCT) in cancer treatment and as drug delivery agents and synthetic intermediates for carbon-carbon cross-coupling reactions. In addition, the use of boron cage compounds in a number of cycloaddition reactions to synthesize unique aromatic species will be reviewed briefly.