Magnetic Nanoparticles Functionalized with Copper Hydroxyproline Complexes as an Efficient, Recoverable, and Recyclable Nanocatalyst: Synthesis and Its Catalytic Application in a Tandem Knoevenagel-Michael Cyclocondensation Reaction

A novel catalyst has been afforded by attaching of a Cu(proline)₂ complex to magnetic nanoparticles through cheap, simple, and readily available chemicals. This catalyst was characterized by Fourier transform infrared, energy-dispersive X-ray, X-ray diffraction, vibrating-sample magnetometry, transmission electron microscopy, scanning electron microscopy, and inductively coupled plasma analyses. The catalytic activity of the Fe₃O₄@NH₂@TCT@HProCu nanocatalyst was investigated in a green and effective synthesis of pyran derivatives in high yields by applying three-component reactions of malononitrile, dimedone, and aldehydes in ethanol. Conversion was high under optimal conditions. The obtained nanocatalyst could be easily separated from the mixture of the reaction and was recyclable nine times via a simple magnet without considerable reduction of its catalytic efficiency. Operational simplicity, high product yields, environmental friendliness, ecofriendliness, economical processing, and easy workup are the features of this methodology.

Green and efficient three-component synthesis of 4H-pyran catalysed by CuFe2O4@starch as a magnetically recyclable bionanocatalyst

The development of simple, practical and inexpensive catalysis systems using natural materials is one of the main goals of pharmaceutical chemistry as well as green chemistry. Owing to the ability of easy separation of nanocatalyst, those goals could be approached by applying heterogeneous bionanocatalyst in combination with magnetic nanoparticles. Starch is one of the most abundant natural polymers; therefore, preparing bionanocatalyst from starch is very valuable as starch is largely available and inexpensive. An ecologically benign and efficacious heterogeneous nanocatalyst was prepared based on a biopolymer, and its attributes and morphology were specified by using Fourier transform infrared spectra, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermal analysis and vibrating sample magnetometer measurements; followed by studying catalytic behaviour of bionanocomposite in a multicomponent reaction to synthesize of 4H-pyran derivatives. 4H-pyran is extremely valuable in pharmaceutical chemistry, and the development of methods for synthesis of different derivatives of 4H-pyran is momentous. Revealing environmentally benign nature, mild condition, easy work-up, low cost and non-toxicity are some of the advantages of this protocol. Besides, the bionanocomposite was recovered using an external magnetic bar and could be re-used at least six times with no further decrease in its catalytic activity.

One-pot synthesis of benzopyrans catalyzed by silica supported dual acidic ionic liquid under solvent-free conditions

A mild and efficient method was developed for the preparation of tetrahydrobenzo[

Cooperative chiral salen TiIV catalysts with built-in phase-transfer capability accelerate asymmetric sulfoxidation in water

Double chiral salen Ti^IV complexes were flexibly combined into a single molecule through a PEG-based di-imidazolium IL bridge, which provided cooperative, phase transfer catalysts for efficient asymmetric sulfoxidation in water with H₂O₂.

Tuning phase behaviour of PEG-functionalized ionic liquids from UCST to LCST in alcohol–water mixtures

Phase behaviour of PEG-functionalized ionic liquids can be tuned from UCST to LCST by the addition of water into aliphatic alcohol.

Biodegradable polyethylene glycol-based ionic liquids for effective inhibition of shale hydration

We report the synthesis of biodegradable polyethylene glycol-based ionic liquids which exhibit potential capability for inhibiting shale hydration.

Thermoregulated Aqueous Biphasic Catalysis of Sonogashira Reactions

A water-based thermoregulated system for Pd-catalyzed Sonogashira reactions is presented, which allows for not only a highly efficient homogeneous catalytic reaction, but also an easy separation/recovery of the catalyst. The novel catalytic system exhibits high efficiency and excellent reusability. In addition, the Sonogashira reactions are performed with Pd(OAc)2 without a copper co-catalyst.

Poly(ethylene glycol)-based ionic liquids: properties and uses as alternative solvents in organic synthesis and catalysis

PEG-based ionic liquids are a new appealing group of solvents making the link between two distinct but very similar fluids: ionic liquids and poly(ethylene glycol)s. They find applications across a range of innumerable disciplines in science, technology, and engineering. In the last years, the possibility to use these as alternative solvents for organic synthesis and catalysis has been increasingly explored. This Review highlights strategies for their synthesis, their physical properties (critical point, glass transition temperature, density, rheological properties), and their application in reactions catalyzed by metals (such as Pd, Cu, W, or Rh) or as organic solvent (for example for multicomponent reactions, organocatalysis, CO2 transformation) with special emphasis on their toxicity, environmental impact, and biodegradability. These aspects, very often neglected, need to be considered in addition to the green criteria usually considered to establish ecofriendly processes.

Bi-functionalized PEG1000 ionic liquid [Imim-PEG1000-TEMPO][CuCl2−]: an efficient and reusable catalytic system for solvent-free aerobic oxidation of alcohols

A reusable catalytic system for efficient aerobic oxidation of alcohols with bi-functionalized PEG₁₀₀₀ ionic liquid [Imim-PEG₁₀₀₀-TEMPO][CuCl₂⁻] was described.