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

Abstract

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.

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

“…CQDs are one of the most encouraging pseudohomogeneous materials with quasi-spherical shapes for cutting-edge technology 17 , 18 . These zero-dimensional nanomaterials show high fluorescence, biocompatibility, chemical inertness and photostability which can be synthesized based on “Green Chemistry” principles from various carbon sources.…”

“…These zero-dimensional nanomaterials show high fluorescence, biocompatibility, chemical inertness and photostability which can be synthesized based on “Green Chemistry” principles from various carbon sources. By selecting the starting materials and reaction conditions in the bottom-up synthesis of CQDs, the physicochemical properties of the product such as size, edge shape, surface functional groups and defects can be changed for use in the chemical and biological applications 17 , 18 .…”

“…As part of our ongoing research program to explore straightforward methods for the fabrication of functionalized nanomaterials by heterocyclic small molecules 26 – 32 , herein, for the first time, we wish to report a basic method for the synthesis of chitosan-based CQDs functionalized by arginine groups. Chitosan, citric acid and arginine dissolve in water to produce a homogenous solution, and then, transfer to the autoclave for one-pot hydrothermal synthesis 17 , 18 , 33 , 34 . Arginine is selected as a surface passivation agent with high amine density.…”

Acute toxicity assessment of polyaniline/Ag nanoparticles/graphene oxide quantum dots on Cypridopsis vidua and Artemia salina

“…Quantum dots (QDs) as colloidal nanocrystals have unique photophysical, electronic and chemical properties due to their large absorption coefficients, high emission and high photostability 15 . Carbon dots are a new type of carbon-based material class and their low-cost and easy preparation are resulting in their innumerable applications 16 , 17 . The green methods are encouraged to synthesize carbon dots because they produce harmless products.…”

Microfibers nanocomposite based on polyacrylonitrile fibers/bismuth oxide nanoparticles as X‐ray shielding material

“…Nanomaterials and nanotechnology as the enabling approaches have promising effects on the conventional structures and processes 9–11 . Nanomaterials exhibit altered and modified performance compared with the bulk counterparts 12–15 . Moreover, it is possible to modify the properties and performance of conventional materials and structures modified by the implementation of nanomaterials 11,16–19 .…”