Nanochannels in Photoactive Polymeric Cu(I) Compatible for Efficient Micellar Catalysis: Sustainable Aerobic Oxidations of Alcohols in Water

Abstract

Upon visible-light irradiation, the heterogeneous polymer of PDI–Cu­(I)–PDI (PDI = perylene diimide) generates charge transfer states that are subsequently quenched by molecular oxygen for their participation in redox activity. This insoluble polymeric Cu­(I) is catalytically active for the oxidation of benzylic alcohols to corresponding aldehydes when suspended in dynamic micelles of PS-750-M. A broad substrate scope, excellent selectivity, and no over-oxidation reveal the catalyst robustness. The catalytic activity, control experiments, and time-dependent DFT calculations show the charge transfer states. The polymeric catalyst is entirely recyclable, as evidenced by the recycle studies using Scott’s recyclability test. The morphology, structure, copper’s oxidation state, and the catalyst’s thermal stability are determined by SEM, XPS, and TGA analysis.

External Catalyst‐Free Oxidation of Benzyl Halides to Benzoic Acids Using NaOH/TBHP in Water

“…Although a variety of catalytic methods based on transition metals [3] and main group based metal‐free catalysts [4] have been developed for oxidation reactions of alcohols, most of these methods suffer from drawbacks, such as the requirement of precious metals, expensive ligands, high temperature, volatile and environmentally unfriendly organic solvents, as well as expensive and toxic additives. Recently, both in industry and academia, there are many reactions being reported of organic synthesis where traditional organic solvents are being replaced by water as a green, inexpensive and safe solvent [5a–h] . However, the development of suitable methods that can help to efficiently isolate the desired compound from the reaction mixture is also an essential part of green chemistry [5i–l] .…”

Shielding Effect of Nanomicelles: Stable and Catalytically Active Oxidizable Pd(0) Nanoparticle Catalyst Compatible for Cross-Couplings of Water-Sensitive Acid Chlorides in Water

“… 37 − 39 Realizing the aforementioned needs while advancing chemistry in water, our laboratory has developed a proline-based amphiphile PS-750-M that mimics dipolar–aprotic solvents, such as DMF, NMP, and DMAc. 40 − 44 Incorporating a tertiary amide group into the amphiphile helps stabilize the NPs and facilitate their delivery into the micellar interior or polar–nonpolar interface. 45 − 47 Our group recently leveraged this amphiphile’s ability to stabilize Pd(II) NPs and employed it in efficient oxidative Mizoroki–Heck type couplings.…”

Reactivity of Styrenes in Micelles: Safe, Selective, and Sustainable Functionalization with Azides and Carboxylic Acids

“…Besides its obvious natural abundance, water is usually considered among the safest reaction solvents. It has been efficiently employed in “on water” and “in water” chemistry for many diverse transformations. − Aqueous micellar catalysis, a major enabler of chemistry in water, has recently gained attraction due to its applications to 4S reaction methodologies. − Many important transformations have been shown to occur in micellar media. − Our group has recently designed an amphiphile PS-750-M that structurally mimics the dipolar-aprotic solvent that enables several transformations which traditionally require DMF, DMAc, NMP, and 1,4-dioxane. − Additionally, the design hypothesis of PS-750-M assisted in gaining insight into how micellar nano-organometallic chemistry occurs. To date, preliminary answers to some fundamental questions are now in hand, such as, where and how chemistry occurs in micellar media and how reaction intermediates (radical, carbene, carbanion) react under the shielding effect of micelles.…”