Self-folded redox/acid dual-responsive nanocarriers for anticancer drug delivery

Self-folded redox/acid dual-responsive nanocarriers (RAD-NCs) are developed for physiologically triggered delivery of anticancer drug. The evidenced redox/acid responsiveness, facile decoration of ligands, and active tumor-targeting capability of RAD-NCs suggest their potential as a promising formulation for tumor-targeted chemotherapy

A dual wavelength-activatable gold nanorod complex for synergistic cancer treatment

A multifunctional gold nanorod complex was formulated for synergistic anticancer treatment upon ultraviolet (UV) and infrared (IR) light dual irradiations

Exploring the mechanism of Stille C-C coupling via peptide-capped Pd nanoparticles results in low temperature reagent selectivity

Herein we systematically probed the atom-leaching mechanism of Pd nanoparticle-driven Stille coupling to further elucidate the fate of the highly active Pd 0 atoms released in solution. In this regard, initial oxidative addition at the particle surface results in Pd atom abstraction for reactivity in solution. As a result, two reaction sites are present, the particle surface and pre-leached Pd atoms, thus different degrees of reactivity are possible. This effect was probed via aryl halide combinations that varied the halogen identity allowing for oxidative addition of two substrates simultaneously. The results demonstrate that the system was highly reactive for iodo-based compounds in the mixture at room temperature; however, reactivity at bromo-based substrates was only observed at slightly elevated temperatures of 40.0 °C. As such, substrate selectivity was evident from the catalytic materials that can be controlled based upon the aryl halide composition and reaction temperature. Furthermore, both inter molecular and intra molecular selectivity is possible, thus raising the degree of reaction complexity that can be achieved. Peptide-capped Pd nanoparticles act as low-temperature, selective catalysts based upon the catalytic mechanism, aryl halide composition, and reaction temperature

CHAPTER 7 - Pd Nanoparticles in C–C Coupling Reactions

Transition metal nanoparticles play an exceedingly important role in driving catalytic reactions. The maximization of the surface-to-volume ratio achieved by materials on the nanoscale is critically important toward enhancing reaction rates; however, the ligands bound to the metallic surface to impart particle stabilization can lead to catalytic poisoning. This is especially true for C–C coupling reactions, where current studies have demonstrated remarkable catalytic activity from a variety of Pd nanoparticles. In this chapter, recent advances in the use of ligand-stabilized Pd nanoparticles to drive C–C coupling reactions are reviewed. Particular emphasis is focused on environmentally-friendly and energy efficient coupling reactions using pseudo-homogeneous catalysts, where modern studies have suggested such capabilities could arise for nanocatalytic materials

Employing high-resolution materials characterization to understand the effects of Pd nanoparticle structure on their activity as catalysts for olefin hydrogenation

Recent developments in nanotechnology have led to the production of new materials with a wide array of applications, particularly in catalysis. Because of their small size, nanoparticles have a maximized surface-to-volume ratio, thus making them attractive targets for use as catalytic structures; however, the number of analytical techniques available to fully characterize materials on such a size scale is quite limited. As a result, a complete understanding of the entire nanoparticle structure remains unclear, especially when considering the active structural motif from which the specific activity arises. Metallic Pd materials have been widely studied due to their immense potential as catalysts for reactions such as olefin hydrogenation and C-C bond synthesis. These materials require surface passivants to act as ligands and stabilize the nanoparticles against aggregation and bulk formation. These ligands have the added value to function as gates that selectively allow reagents to reach the active surface of the Pd nanoparticles for chemical turnover. This accounts for the observed selectivities of the catalysts with the corresponding changes in the turnover frequency values. Here we present a broad overview of recent advances in the use of Pd nanoparticles for the industrially important hydrogenation reaction with a focus on characterizing and understanding the base structural effects that give rise to the catalytic activity

Effects of Substrate Molecular Structure on the Catalytic Activity of Peptide-Templated Pd Nanomaterials

Advancing catalytic processes toward sustainable conditions is necessary to maintain current production levels in light of dwindling natural resources. Nanomaterial-based catalysts have been suggested as a possible route to achieve this goal; however, the effects of particle structure on the reaction remain unclear. Furthermore, for each reaction, different substrates are likely to be used that vary the molecular size, functional group composition, and reactive moiety site that could significantly alter the reactivity of nanomaterial-based catalysts. In this contribution, we have studied the effects of the molecular substrate structure on the reactivity of peptide-templated Pd nanomaterials with selectable morphologies. In this regard, spherical, ribbon-like, and networked metallic nanomaterials were studied that demonstrated significant degrees of reactivity of olefin hydrogenation using the substrates that varied the molecular size and reactive group position. The results demonstrated that substrate isomerization, rather than molecular structure, plays a significant role in attenuating the reactivity of the materials. Furthermore, the Pd structures demonstrated the ability to drive multistep reactivity for the complete hydrogenation of substrates with multiple reactive groups. Such results advance the structure/function relationship of nanocatalysis that could be important in addressing future sustainability goals