Unveiling the catalytic nature of palladium-N-heterocyclic carbene catalysts in the alpha-alkylation of ketones with primary alcohols

We report herein the synthesis of four new Pd-PEPPSI complexes with backbone-modified N-heterocyclic carbene (NHC) ligands and their application as catalysts in the alpha-alkylation of ketones with primary alcohols using a borrowing hydrogen process and tandem Suzuki-Miyaura coupling/alpha-alkylation reactions. Among the synthesized Pd-PEPPSI complexes, complex 2c having 4-methoxyphenyl groups at the 4,5-positions and 4-methoxybenzyl substituents on the N-atoms of imidazole exhibited the highest catalytic activity in the alpha-alkylation of ketones with primary alcohols (18 examples) with yields reaching up to 95%. Additionally, complex 2c was demonstrated to be an effective catalyst for the tandem Suzuki-Miyaura-coupling/alpha-alkylation of ketones to give biaryl ketones with high yields. The heterogeneous nature of the present catalytic system was verified by mercury poisoning and hot filtration experiments. Moreover, the formation of NHC-stabilized Pd(0) nanopArticles during the alpha-alkylation reactions was identified by advanced analytical techniques.We are grateful to the Ege University Scientific Research Projects Coordination (FYL-2019-21171) and the Turkish Academy of Science (TUBA) for the financial support. M. O. thanks the Turkiye Scholarships for the fellowship. Z. E. thanks to the Council of Higher Education of Turkey for 100/2000 CoHE Doctoral Scholarship and TUBITAK 2211/C National Ph.D. Scholarship Program in the Priority Fields in Science and Technology.Ege University Scientific Research Projects Coordination [FYL-2019-21171]; Turkish Academy of Science (TUBA); Turkiye Scholarships; Council of Higher Education of Turkey; TUBITAK 2211/C National Ph.D. Scholarship Program in the Priority Fields in Science and Technolog

Antimicrobial Nanomaterials: A Review

Microbial colonization on various surfaces is a serious problem. Biofilms from these microbes pose serious health and economic threats. In addition, the recent global pandemic has also attracted great interest in the latest techniques and technology for antimicrobial surface coatings. Incorporating antimicrobial nanocompounds into materials to prevent microbial adhesion or kill microorganisms has become an increasingly challenging strategy. Recently, many studies have been conducted on the preparation of nanomaterials with antimicrobial properties against diseases caused by pathogens. Despite tremendous efforts to produce antibacterial materials, there is little systematic research on antimicrobial coatings. In this article, we set out to provide a comprehensive overview of nanomaterials-based antimicrobial coatings that can be used to stop the spread of contamination to surfaces. Typically, surfaces can be simple deposits of nanomaterials, embedded nanomaterials, as well as nanotubes, nanowires, nanocolumns, nanofibers, nanoneedles, and bio-inspired structures