In the present study, an ecofriendly and zero-cost approach has been demonstrated for the preparation of carbon quantum dots by one-pot hydrothermal treatment of leaf extracts of neem (Azadirachta indica). The as-synthesized neem carbon quantum dots (N-CQDs) exhibited high fluorescent quantum yields (QYs) up to 27.2%. Moreover, N-CQDs also act with a peroxidase-like-mimetic activity toward the oxidation of peroxidase substrate 3,3′,5,5′-tetramethyl­benzidine (TMB) in association with hydrogen peroxide (H2O2). Further, the kinetics of peroxidase-like catalytic activity follows the Michaelis–Menten and ping-pong pathway. In addition, the H2O2 sensitive TMB oxidation motivated the colorimetric detection of H2O2 which showed linearity from 0.1 to 0.5 mmol/L with a detection limit (LOD) of 0.035 mmol/L. Furthermore, the blue colors of oxidized TMB (ox-TMB) were selectively reduced in native TMB with ascorbic acid (AA) without any interference of other reducing agents. The linear range of AA detection was lying between 5 and 40 μM with a LOD up to 1.773 μM. The practicability assay of the proposed sensing system toward the detection of AA was also investigated in real sample analysis such as common fruits which showed good sensitivity to the presence of AA. Therefore, this convenient, ecofriendly, and cost-effective peroxidase-based sensing system opens a new platform for analysis of AA in real samples and in complex biological systems.

The regioselective conversion of C-H bonds into C-Si bonds is extremely important owing to the natural abundance and non-toxicity of silicon. Classical silylation reactions often suffer from poor functional group compatibility, low atom economy, and insufficient regioselectivity. Herein, we disclose a template-assisted method for the regioselective para silylation of toluene derivatives. A new template was designed, and the origin of selectivity was analyzed experimentally and computationally. An interesting substrate-solvent hydrogen-bonding interaction was observed. Kinetic, spectroscopic, and computational studies shed light on the reaction mechanism. The synthetic significance of this strategy was highlighted by the generation of a precursor of a potential lipophilic bioisostere of γ-aminobutyric acid (GABA), various late-stage diversifications, and by mimicking enzymatic transformations.

General consideration S3 Experimental section S3 2.1 Preparation of starting materials S3 -S11 2.2 Optimization details for meta-CH alkynylation with (bromoethynyl)triisopropylsilane Screening of scaffolds S12 -S19 S20 2.3 2.3.1.a 2.3.1.b 2.3.1.c 2.3.1.d General procedure for palladium catalyzed meta-selective CH alkynylation of arene General procedure for palladium catalyzed meta-selective sequential hetero difunctionalization of arene General procedure for gram scale synthesis of meta-alkynylated protocol General procedure for directing group removal of meta-alkynylated protocol General procedure for different application of meta-alkynylated product S20 S21-S22 S23 S23 S24-S25 2.4 Characterization data of meta-alkynylated products S25 -S60 2.5 Mechanistic studies S60 -S66 2.6 Computational methods S67 -S115 References S115 -S122 NMR spectra S123 -S205S10 TBDMSO Br Ph ((1-(bromoethynyl)-4-phenylcyclohexyl)oxy)(tert-butyl)dimethylsilane: 1 H NMR (400 MHz, CDCl 3 ) δ 7.33 (t,

A Pd(II)-catalyzed highly regioselective γchalcogenation, thioarylation, and selenoarylation of aliphatic carboxylic acids has been demonstrated. The present protocol provides a direct access to make structural modifications of αamino acids such as valine, isoleucine, and tert-leucine with high diastereoselectivity (up to 52:1). Sequential heterobifunctionalizations have been carried out at γ-sp 3 C−Hs, resulting in desymmetrization of quaternary centers. The applicative potential of the chalcogenated products was exhibited by using them as precursors for the synthesis of the biologically relevant benzothiepinone moiety. Preliminary studies were carried out to gain insights into the mechanism.

On–off–on detection of Hg2+ and GSH using green-synthesized CQDs from T. indica leaves for the first time.

Directed C−H functionalization has been realized as a complementary tool to the traditional approaches for a straightforward access of non‐proteinogenic amino acids; albeit such a process is restricted mostly up to the γ‐position. In the present work, we demonstrate the diverse (hetero)arylation of amino acids and analogous aliphatic amines selectively at the remote δ‐position by tuning the reactivity controlled by ligands. An organopalladium δ‐C(sp3)−H activated intermediate has been isolated and crystallographically characterized. Mechanistic investigations carried out experimentally in conjunction with computational studies shed light on the difference in the mechanistic picture depending on the substrate structure.

Synthesis of nitrogen–sulphur dual-doped carbon quantum dots and their peroxidase like mimetic activity for the colorimetric detection of H2O2 and glutathione in human blood serum.

An eco-friendly and economic efficient approach has been developed for the photoinduced synthesis of more stable AuNPs using an aqueous extract of Croton bonplandianum (AEC) as a reducing and capping agent. The reaction mixture of AEC and HAuCl 4 .xH 2 O, when exposed to sunlight turned purple which primarily confirmed the biosynthesis of AuNPs. The biosynthesis was monitored using UV− vis spectroscopy which exhibited a sharp SPR band at 530 nm after 16 min of sunlight exposure. The parameters affecting the synthesis of AuNPs such as sunlight exposure, AEC inoculum dose, and HAuCl 4 .xH 2 O concentration were also optimized. The HR-TEM study revealed that, as the metal ion concentrations increased, the average size and anisotropic nature of the AuNPs increased. The X-ray diffraction pattern of AuNPs synthesized confirmed the formation of face-centered cubic crystal lattice of metallic gold. The involvement of polyphenolics in the synthesis of AuNPs was confirmed by comparing the FTIR analysis of pure tannic acid, AEC, and pre-and postannealed AuNPs. The XPS analysis corroborated the presence of two individual peaks attributed to the Au 4f 7/2 and Au 4f 5/2 binding energies which corresponded to the presence of metallic gold. The AuNPs thus obtained showed peroxidase-like mimicking activity which catalyzed the oxidation of TMB to oxTMB with the development of blue color and absorption spectra at 652 nm. However, the presence of GSH caused further reduction of oxTMB. This detection experiment showed an excellent linear relationship between 1 and 40 μM with a limit of detection of 0.013 μM. In addition to this, the significant recovery of GSH from human blood serum advocated that the developed system was simple and sensitive for the real sample analysis.