Supported Noyori-Ikariya catalysts for asymmetric transfer hydrogenations and related tandem reactions

UV-light crosslinked photocatalytic polymer gels for batch and continuous flow reactions

“…57 Others have studied this reaction using scaffolds for Eosin Y (such as cotton threads, Amberlite Resins, polyurethane foams, or chitin spheres). 28,44,46,54 Rose bengal-based materials have also been studied on chitosan, and yields of 92% of thioanisole in 6 hours of blue light irradiation were obtained. 58 A volumetric ratio of 8 : 2 acetonitrile to water for the solvent choice for this reaction was based off of optimizations performed by Sridhar et al 59 and Chu et al 43 It is hypothesized that this mixture may combine the benefits that acetonitrile results in a relatively longer excited state lifetime of singlet oxygen 60 and it is thought that the addition of water aids in the prevention of catalyst agglomeration for some catalyst types.…”

“…Overall, results from our materials suggest faster kinetics than were observed by Chu et al, who performed this reaction using Eosin Y coupled to cotton thread (EY@cotton) catalysts and found 45% product yield after 28 hours (green light, λ max = 530 nm, 0.45 mW cm −2 ) even with air being bubbled through the system as an additional O 2 supply. 28 For a comparison of this catalyst's performance compared to other similar systems based off of Eosin Y, the reader is referred to a summary table prepared by Peng et al 63 The degree of crosslinking was investigated to further understand the impact of the benzophenone groups on the gel's photocatalytic performance. Riga et al found that increased amounts of benzophenone groups at 15 mol% resulted in higher amounts of gel compared to 5 mol% on silica wafers when controlled for the same input of UV light energy for crosslinking.…”

“…42 As will be discussed, Eosin Y and Rose Bengal can be readily modified for heterogenization. Examples of Eosin Y-based heterogeneous photocatalysts include cotton threads (Eosin Y@cotton), 43 Eosin Y attached to poly(urethane)-based scaffolds, 44 interpenetrating polymer networks (IPNs) comprised of poly(ethylene glycol) diglycidyl ether and 3-(diethylamino)propylamine, and 1,2-bis(2aminoethoxy)ethane as a crosslinker, 45 as well as Eosin-Y functionalized Amberlite IRA 900 chloride resin. 46 Each system offers means for recovery through removal of the catalyst by simple means such as using filter paper.…”

Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

“…699 As with other transition-metal-catalyzed reactions, ATH catalysts have been supported on various materials, including ILs, in order to allow easy separation of products and recovery and reutilization of catalyst. 700 ATH reactions with ILs are summarized in Table 11 and Figures 34 and 35 and include ILs as solvent associated with neutral or ionic ligands or complexes, tagged IL ligands or complexes, and polymer ILs. Acetophenone is generally the benchmark reaction, and scope and recycle studies are often also evaluated.…”

Boosting structural variety and catalytic activity of porphyrinic metal–organic frameworks by harnessing bifunctional ligands

“…One promising approach to overcome these issues is immobilizing the catalysts on a solid support. 34 However, it remains challenging to anchor different catalysts on solid supports in an ordered fashion. Therefore, developing efficient heterogeneous catalysts for tandem reactions is necessary.…”