AA research Group from the Department of Organic Chemistry and Inorganic Chemistry at University of Alcalá (Spain) has designed catalysts suitable for organic synthesis processes based on supported N-heterocyclic carbene (NHC) complexes of palladium, which are magnetically separable after their use, reusable and resistant to metal leaching, and useful in carbon-carbon coupling reactions.
The group is looking for companies in the chemical and pharmaceutical sectors to reach licensing agreements or collaboration and commercial agreements for technical assistance.
New and innovative aspects
These catalysts are well defined, and after their use are easily separated from the products without degradation, they can be reused and do not contaminate the product with leached palladium, resulting in products of the catalysis with contents of less than ten parts per million, and sometimes even in the order of parts per billion, after magnetic separation of the particles.
Main advantages of its use
- Activity under mild conditions and in aqueous media.
- Robustness of the catalyst, which leads to a very high productivity.
- Ease separation from the catalytic products.
- Very low levels of palladium leaching, leading to products in which further work up to eliminate that metal it is not necessary.
Specifically, this invention involves the synthesis of (NHC)palladium complexes (PCs) with suitable substituents for their covalent grafting onto magnetic nanoparticles (MPs), resulting in nanomaterials containing the supported complexes (CMPs) as unique and well defined species of palladium tightly bound to the support. The CMPs give rise to stable dispersions in water and catalyze carbon-carbon bond formation processes in aqueous medium under mild conditions.
The technical problem solved by these materials is, on one hand, that the superparamagnetism of the CMP-core allows their complete and easy separation from the products at the end of the reaction by applying a magnetic field, and, on the other hand, that the design of the supported catalysts allows their recovery without appreciable degradation, they can be reutilized reaching very high values of TON (turnover number), and do not suffer metal leaching, or it is negligible, resulting in catalytic products with palladium contents below ten parts per million –in certain cases in the order of parts per billion- after the magnetic separation of the particles.
- A first aspect of the invention is related to new PCs of typologies I, II, and III.
- A second aspect of the invention is related to the synthetic methods for the new PCs of types I, II, III and their precursors.
Specifically, the PC to be supported comprises mono(NHC), bis(NHC) and bis(NHC)-chelate complexes;.
- A third aspect of the invention is related to procedures for the immobilization of types I, II, and III onto magnetic particles (MPs) of iron oxide to generate magnetic particles containing the supported complexes (CMPs)
The MPs used as supports are commercially available and they are characterized by diameters in the range of tens to hundreds of nanometers, by an iron oxide core, and by an inert coating such as silica or polystyrene.
The general immobilization procedure involves condensation reactions, preferably towards the formation of siloxane or amide groups, between the PCs and the corresponding MPs dispersed in organic solvents, or preferably in an hydroalcoholic medium in the presence of small amounts of nonionic surfactants with high hydrophobic-hydrophilic balance (HLB > 15, used below the critical micelle concentration), in the presence of a carbodiimide as a coupling agent, the addition of the PC dissolved in a very polar solvent, a constant mechanical stirring, and a sequence of washings comprising the trapping of the CMPs with an external magnet and the decantation of the solutions.
- A fourth aspect of the invention is related to the use of such CMPs as catalysts for carbon-carbon coupling reactions.
The present invention also concerns the uses of CMPs in carbon-carbon coupling reactions, particularly Mizoroki-Heck and Suzuki-Miyaura with aryl halides, dispersed in an aqueous medium and under mild conditions, and their reutilization as catalysts after effective separation of the products by an external magnet. Their kinetic profiles (% conversion vs. time), their recyclability in successive tests of catalysis-recovery-reuse, the endurance of their properties in the recycled series and the leaching suffered by the CMPs in them, have been analyzed.
The essential features of the CMPs of the present invention are: they catalyze carbon-carbon coupling reactions under mild conditions, they are easily separated from the reaction medium, can be reused in series of numerous recyclings, and are very robust to degradation and hardly suffer leaching of palladium.
- For organic synthesis processes
- Inc chemical and pharmaceutical companies.
Intellectual property status
Current development status
Desired business relationship
Commercial cooperation or licensing agreements with chemical and pharmaceutical companies.