Nanoparticles of gold prepared by condensation of gold vapor in cold pentanone serve as active catalysts for the polymerization of an alkylsilane C18H35SiH3 with water, to form nanowires and filaments. This reaction takes place under relatively mild conditions (refluxing pentanone).
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/ja035046h | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States.
Enthalpy is often the focal point when designing monomers for polymer circularity, but much less is explored on how entropy can be exploited to create polymers with synergistic circularity and properties. Here, we design a series of spiro-lactones (SLs) with closed-chain cycloalk(en)yl substituents at the α,α-position of δ-valerolactone (δVL), which, when combined with the parent δVL and -α,α-dialkyl-substituted δVL with open-chain alkyl groups, provide a desired platform for exploring the circular polymer design by focusing on the entropy change of polymerization. These SLs exhibit finely balanced (de)polymerizability that is regulated chiefly by entropy differentiation, allowing both the facile synthesis of polyester PSLs ( up to 1000 kg mol) in a living fashion and selective depolymerization of the PSLs to completely recover monomers under mild conditions (using a recyclable catalyst at 100 °C).
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
While synthesizing circular polymers with telechelic polyolefin building blocks recently emerged as a promising strategy for addressing conventional polyethylenes' sustainability challenges, the lack of telechelic PP (PP) with sufficient difunctional purity for polycondensation has been limiting the development of circular polypropylenes with PP-like structures and properties. Here we described a combined approach of coordinative chain transfer polymerization and transition-metal-catalyzed quenching reaction with various acyl chlorides, affording PPs with a high difunctional ratio (up to ∼99%) and broad end functional group scope. The steric effect of polymeryl-Zn species and the role of Pd catalyst were revealed by DFT.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Chemistry, Indian Institute of Technology Patna, Patna 801106, Bihar, India.
Covalent organic frameworks (COFs) are crystalline porous materials bearing well-ordered two- or three-dimensional molecular tectons in their polymeric skeletal framework. COFs are structurally robust as well as physiochemically stable. Currently, these are being developed for their use as "heterogeneous catalysts" for various organic transformations.
View Article and Find Full Text PDFAmino Acids
January 2025
Tissue Engineering and Regenerative Medicine Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
In recent years, the use of cationic peptides as alternative drugs with anticancer activity has received attention. In this study, the targeted release of curcumin (Cur) and CM11 peptide alone and together against hepatocellular carcinoma (HCC) was evaluated using chitosan nanoparticles (CS NPs) coated with Pres1 that target the SB3 antigen of HCC cells (PreS1-Cur-CM11-CS NPs). SB3 protein is the specific antigen of HCC and the PreS1 peptide is a part of the hepatitis B antigen, which can specifically bind to the SB3 protein.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, China.
Frustrated Lewis pair chemistry (FLP) occupy a crucial position in nonmetal-mediated catalysis, especially toward activation of inert gas molecules. Yet, one formidable issue of homogeneous FLP catalysts is their instability on preservation and recycling. Here we contribute a general solution that marries the polyhedral oligomeric silsesquioxane (POSS) with a structurally specific frustrated Lewis acid to fabricate porous polymer networks, which can form water-insensitive heterogeneous FLP catalysts upon employing Lewis base substrates.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!