Abstract
In the present work, the rich chemistry of rhodium/phosphine complexes, which are applied as homogeneous catalysts to promote a wide range of chemical transformations, has been used to showcase how the in situ generation of precatalysts, the conversion of precatalysts into the actually active species, as well as the reaction of the catalyst itself with other components in the reaction medium (substrates, solvents, additives) can lead to a number of deactivation phenomena and thus impact the efficiency of a catalytic process. Such phenomena may go unnoticed or may be overlooked, thus preventing the full understanding of the catalytic process which is a prerequisite for its optimization. Based on recent findings both from others and the authors’ laboratory concerning the chemistry of rhodium/diphosphine complexes, some guidelines are provided for the optimal generation of the catalytic active species from a suitable rhodium precursor and the diphosphine of interest; for the choice of the best solvent to prevent aggregation of coordinatively unsaturated metal fragments and sequestration of the active metal through too strong metal–solvent interactions; for preventing catalyst poisoning due to irreversible reaction with the product of the catalytic process or impurities present in the substrate.
Highlights
The term “catalysis” was first introduced by the Swedish chemist Jöns Jacob Berzelius in a report published in 1835 by the Swedish Academy of Sciences [1]
With DPEPhos a species is formed in which the diphosphine, the diolefin, and a chloride ligand bind to rhodium to give a penta-coordinated complex (Figure 2c) [50]
InInthe therich richchemistry chemistry rhodium/phosphine complexes, are applied thepresent present work, work, the of of rhodium/phosphine complexes, whichwhich are applied as ashomogeneous homogeneouscatalysts catalysts to promote a wide range of chemical transformations, has been used to promote a wide range of chemical transformations, has been used to to showcase how the in situ of precatalysts, precatalysts,the theconversion conversion precatalysts showcase how the in situ generation generation of of of precatalysts intointo the the active species, as well as the reaction of the catalyst itself with other components in the reaction active species, as well as the reaction of the catalyst itself with other components in the reaction medium additives) can canlead leadtotoaanumber numberofofdeactivation deactivation phenomena
Summary
The term “catalysis” was first introduced by the Swedish chemist Jöns Jacob Berzelius in a report published in 1835 by the Swedish Academy of Sciences [1]. Catalysis is the macroscopic manifestation of the reduction of the activation energy of an exergonic reaction It is as such a purely kinetic phenomenon; Berzelius did not know the concept of reaction rate yet and he could only describe known findings phenomenologically. Is a substance that increases thethe rateswitch of a reaction, Catalysis widely applied both in reduces industry and academia [14,15]: from a reaction, and an inhibitor, which instead it [9]. Improvement of the catalyst productivity and efficiency, both in terms of activity and selectivity in the desired product, requires knowledge of the chemical transformations the catalyst undergoes during the course of the reaction. In several cases the acquired knowledge has allowed improvement of the catalyst performance considerably
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
