N-Isocyaniminotriphenylphosphorane (Ph3PNNC) as a metal-free catalyst for the synthesis of functionalized isoindoline-1-ones

A pseudohomogeneous nanocarrier based on carbon quantum dots decorated with arginine as an efficient gene delivery vehicle

A pseudohomogeneous carrier as an emerging term refers to subnanometric carbon-based vehicle with a high ability to interact with genetic materials to form stable carboplex and successfully transfer them into the cell which will result in inhibiting or expressing of therapeutic genes. Chitosan is a non-toxic polyaminosaccharide used as a precursor in the presence of citric acid to produce carbon quantum dots (CQDs), which decorated with arginine as a surface passivation agent with high amine density in hydrothermal methodology. The Arginine-CQDs are comprehensively characterized by Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), Atomic force microscopy (AFM), field emission scanning electron microscope (FE-SEM), Energy-dispersive X-ray (EDX) mapping, fluorescence, High-resolution transmission electron microscopy (HR-TEM), zeta potential and X-ray powder diffraction (XRD). In this regard, for the first time, carboplex are formed by electrostatic conjugating of Arginine-CQDs with DNA to protect it from enzymatic degradation. Moreover, the carboplex, like the chitosan precursor, has not shown toxicity against AGS cell line. Interestingly, the Arginine-CQDs have exhibited an excellent ability to overcome cell barriers to deliver into cells compared to chitosan at the same weight ratio. The Arginine-CQDs/pEGFP (W/W) nanocomplex, not only lead to transfection with a relatively higher efficiency than PEI polymer, which is the "golden standard", but carboplex also demonstrates no significant toxicity. Indeed, the EGFP expression level has reached to 2.4 ± 0.2 via Arginine-CQDs carboplex at W/W 50 weight ratio. To the best of our knowledge, this is the first report includes chitosan-based CQDs functionalized by arginine which is applied to serve as a pseudohomogeneous vehicle for gene transfection.

Pseudohomogeneous metallic catalyst based on tungstate-decorated amphiphilic carbon quantum dots for selective oxidative scission of alkenes to aldehyde

Herein, we present an interesting role of tungstate-decorated amphiphilic carbon quantum dots (A-CQDs/W) in the selective oxidative cleavage of alkenes to aldehydes. In this work, for the first time, we disclose an unprecedented tungstate-based oxidative system incorporating A-CQDs as a bridge to the homogeneous catalyst for selective and efficient cleavage of a wide substrate scope of alkenes into aldehydes. The A-CQDs/W were synthesized via a one-step hydrothermal synthesis approach using 1-aminopropyl-3-methyl-imidazolium chloride and stearic acid for the surface modification, following by anion-exchange to immobilize WO₄^-2 to A-CQDs. The A-CQDs/W act as a pseudohomogeneous metallic catalyst (PMC) for selective oxidative scission of alkenes under phase transfer catalysts (PTC) free condition without over oxidation to acids, using water and H₂O₂ as a green oxidant. Thanks to the sub-nanometric size and novel engineered chemical structure, this PMC and reactants are in the same phase, besides they can be easily isolated from each other by extraction processes. The synthesized PMC exhibited excellent solubility and stability in various solvents. Interestingly, the system's high conversion efficiency was preserved even after eight catalytic cycles indicating the recyclability of the synthesized PMC. We believe that this study provides a significant and conceptually novel advance in oxidative cleavage chemistry.

Amphiphilic Carbon Quantum Dots as a Bridge to a Pseudohomogeneous Catalyst for Selective Oxidative Cracking of Alkenes to Aldehydes: A Nonmetallic Oxidation System

The oxidative cleavage of alkenes to the corresponding aldehydes using new amphiphilic carbon quantum dots (A-CQDs) as a pseudohomogeneous carbocatalyst is achieved for the first time through green and sustainable chemical processes. In this work, we successfully design a recyclable pseudohomogeneous catalyst based on A-CQDs, which is decorated with 1-aminopropyl-3-methyl-imidazolium chloride and stearic acid. The functionalization is conducted to introduce a hydrophilic/hydrophobic functionality on the surface of the catalyst to achieve high catalyst availability in polar and nonpolar media with the green goal of eliminating organic (co)solvents and additives. This amphiphilic carbocatalyst provides high mass transferability to the biphasic system, which is beneficial to promoting the oxidative cracking of a variety of olefins into corresponding aldehydes with a substrate/A-CQD ratio of 150. Around 87% of the substrates are converted to the related aldehydes using the carbocatalyst in the presence of H₂O₂, in pure water, without using a phase-transfer catalyst or any additives and organic solvents, which is comparable with the current metal-based cleavage systems. Surprisingly, A-CQDs exhibit high catalytic activity for the scission of electron-deficient C═C bond of coumarin derivatives, accompanied by the cleavage of C-O bonds to produce the corresponding salicylaldehyde derivatives without overoxidation to acid. As a brief conclusion, A-CQDs exhibit high conversion efficiency without significant loss of activity even after six catalytic cycles. The conversion of alkenes into aldehydes is fast and high-throughput without overoxidation to acids and is accompanied by excellent solubility and stability in various solvents. Moreover, the product and the catalyst are recoverable from the reaction medium by simple extraction. So, this pseudohomogeneous carbocatalyst promises new horizons in imminent "catalytic age". All in all, this paper provides a significant and novel advancement in carbocatalyst chemistry.

Targeted Development of Sustainable Green Catalysts for Oxidation of Alcohols via Tungstate-Decorated Multifunctional Amphiphilic Carbon Quantum Dots

Achieving green and sustainable chemical processes by replacing organic solvents with water has always been one of the green chemistry goals and a challenging topic for chemists. However, the poor solubility of organic materials is a major limitation to achieving this goal, especially in alcohol oxidation. In this contribution, the development and design of amphiphilic catalysts via abundant, safe, cheaper, and more biocompatible sources have received notable attention. To this purpose, herein, our group successfully synthesized a new multifunctional amphiphilic carbon quantum dot (CQD) composed of 1-aminopropyl-3-methyl-imidazolium chloride ([APMim][Cl]), dodecylamine (DDA), and citric acid (CA) (denoted as CQDs@DDA-IL/Cl) using a one-pot hydrothermal route. The CQDs@DDA-IL/Cl was then utilized as an amphiphilic stabilizer for anchoring tungsten ions using an anion-exchange method (marked as CQDs@DDA-IL/W). The CQDs@DDA-IL/W as a reusable catalyst selectivity mediated the oxidation of alcoholic substrates with stoichiometric H₂O₂ in water solvent. The extraordinary performance of our catalyst was attributable to the coexistence of ionic liquid (IL) and DDA upon the surface of the CQDs@DDA-IL/W, which plays a main duty in the hydrophobic/hydrophilic balance, and significantly increase the catalyst compatibility in the aqueous medium with the purpose of removing organic solvents. As a result, the great mass transfer occurs in the two-phase medium using this amphiphilic nanocatalyst without any phase transfer catalyst (PTC) or other additives. The 100% selectivity, excellent turnover number (TON) and turnover frequency (TOF), high yield, almost complete and fast conversion of alcohol to the desired aldehydes and ketones without more oxidation, and easy and no-trouble isolation of product and catalyst are outstanding features of this catalytic system.