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With the increased prevalence of antibiotic-resistant infections, there is an urgent need for innovative antimicrobial treatments. One such area being actively explored is the use of self-assembling cationic polymers. This relatively new class of materials was inspired by biologically pervasive cationic host defense peptides. The antimicrobial action of both the synthetic polymers and naturally occurring peptides is believed to be complemented by their three-dimensional structure. In an effort to evaluate shape effects on antimicrobial materials, triblock polymers were polymerized from an assembly directing terephthalamide-bisurea core. Simple changes to this core, such as the addition of a methylene spacer, served to direct self-assembly into distinct morphologies-spheres and rods. Computational modeling also demonstrated how subtle core changes could directly alter urea stacking motifs manifesting in unique multidirectional hydrogen-bond networks despite the vast majority of material consisting of poly(lactide) (interior block) and cationic polycarbonates (exterior block). Upon testing the spherical and rod-like morphologies for antimicrobial properties, it was found that both possessed broad-spectrum activity (Gram-negative and Gram-positive bacteria as well as fungi) with minimal hemolysis, although only the rod-like assemblies were effective against Candida albicans.

Side-chain polymers have the potential to be excellent dopant-free hole-transporting materials (HTMs) for perovskite solar cells (PSCs) because of their unique characteristics, such as tunable energy levels, high charge mobility, good solubility, and excellent film-forming ability. However, there has been less research focusing on side-chain polymers for PSCs. Here, two side-chain polystyrenes with triphenylamine substituents on carbazole moieties were designed and characterized. The properties of the side-chain polymers were tuned finely, including the photophysical and electrochemical properties and charge mobilities, by changing the positions of triphenylamine substituents on carbazole. Owing to the higher mobility and charge extraction ability, the polymer P2 with the triphenylamine substituent on the 3,6-positions of the carbazole unit showed higher performance with power conversion efficiency (PCE) of 18.45%, which was much higher than the PCE (16.78%) of P1 with 2,7-positions substituted. These results clearly demonstrated that side-chain polymers can act as promising HTMs for PSC applications and the performance of side-chain polymers could be optimized by carefully tuning the structure of the monomer, which provides a new strategy to design new kinds of side-chain polymers and obtain high-performance dopant-free HTMs.

Heterogeneous single-metal-site catalysts (HSMSCs) have attracted considerable interest, but most studies have focused on the metal atoms in the active site while ignoring the key role of ligands. The unique coordination environment of a single-site catalyst is crucial for realizing its potential. Constructing this kind of catalyst via a feasible and practical fabrication method is challenging. Herein, a single-site Pd catalyst with iodide ligands supported on activated carbon (Pd1/AC) was successfully fabricated by atomic dispersion of large Pd nanoparticles (NPs). Intermediate I• radicals were detected during the atomic dispersion process of Pd NPs by in situ imaging photoelectron photoion coincidence spectroscopy (in situ iPEPICO) with vacuum ultraviolet synchrotron radiation. The molecular structure of single-site Pd was established as [Pd­(CO)­I4(OAC)]2– through combined characterization. Alkyne dialkoxycarbonylation with high selectivity toward 1,4-dicarboxylic acid esters (>94%) and high acetylene conversion (>99%) was achieved. A sulfonic promoter on the Pd1/AC catalyst for alkyne dialkoxycarbonylation was avoided because of the iodide ligand. Good durability and a broad substrate scope were successfully achieved.

A heterogeneous hydrocarboxylation process of olefins to obtain carboxylic acids with one more carbon was first realized using a single-Rh-site catalyst formed on porous organic polymer (Rh1/POPs). The in-situ formation...

Enantioselective synthesis of bicarbocyclic structures with an all-carbon quaternary stereocenter through sequential cross metathesis and intramolecular Rauhut-Currier reaction." Tetrahedron Letters 51, no. 19 (2010Letters 51, no. 19 ( ): 2636Letters 51, no. 19 ( -2638

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