Assemblies of Polyacrylonitrile-Derived Photoactive Polymers as Blue and Green Light Photo-Cocatalysts for Cu-Catalyzed ATRP in Water and Organic Solvents

Photoluminescent nanosized quasi-spherical polymeric assemblies prepared by the hydrothermal reaction of polyacrylonitrile (PAN), ht-PLPPAN, were demonstrated to have the ability to photo-induce atom transfer radical polymerization (ATRP) catalyzed by low, parts per million concentrations of CuII complex with tris(2-pyridylmethyl)amine (TPMA). Such photo induced ATRP reactions of acrylate and methacrylate monomers were performed in water or organic solvents, using ht-PLPPAN as the photo-cocatalyst under blue or green light irradiation. Mechanistic studies indicate that ht-PLPPAN helps to sustain the polymerization by facilitating the activation of alkyl bromide species by two modes: 1) green or blue light-driven photoreduction of the CuII catalyst to the activating CuI form, and 2) direct activation of dormant alkyl bromide species which occurs only under blue light. The photoreduction of the CuII complex by ht-PLPPAN was confirmed by linear sweep voltammetry performed under illumination. Analysis of the polymerization kinetics in aqueous media indicated even though CuI complexes comprised only 1–1.4% of all Cu species at equilibrium, they exhibited high activation rate constant and activated the alkyl bromide initiators five to six orders of magnitude faster than ht-PLPPAN.

Tuning Reactivity of Micellar Nanoreactors by Precise Adjustments of the Amphiphiles and Substrates Hydrophobicity

<p>Polymeric assemblies, such as micelles, are gaining increasing attention due to their ability to serve as nanoreactors for the execution of organic reactions in aqueous media. The ability to conduct transformations, which have been limited to organic media, in water is essential for the further development of the important fields of green</p><p>catalysis and bioorthogonal chemistry, among other fields. In light of the recent progress in the expanding the scopes of reactions that can be conducted using nanoreactors, we aimed to gain deeper understanding of the roles of the hydrophobicity of both the core of micellar nanoreactors and the substrates on the reaction rates in water. Towards this goal we designed a set of metal-loaded micelles, composed of PEG-dendron amphiphiles and studied their ability to serve as nanoreactors for a palladium mediated depropargylation reaction of four substrates with different LogP values. Using dendrons as the hydrophobic block, allowed us to fine tune the lipophilicity of the dendritic end-groups and study how precise structural changes in the hydrophobicity of the amphiphiles affect the reaction rates. The kinetic data revealed linear relations between the rate constants and the hydrophobicity of the amphiphiles (estimated by the dendron’s</p><p>cLogP), while exponential dependence was obtained for the lipophilicity of the substrates (estimated by their LogP values). Our results demonstrate the vital contributions of the hydrophobicity of both the substrates and amphiphiles on the lipo-selectivity of nanoreactors, illustrating the potential of tuning hydrophobicity as a tool for optimizing</p><p>the reactivity and selectivity of nanoreactors.</p>

Tuning Reactivity of Micellar Nanoreactors by Precise Adjustments of the Amphiphiles and Substrates Hydrophobicity

<p>Polymeric assemblies, such as micelles, are gaining increasing attention due to their ability to serve as nanoreactors for the execution of organic reactions in aqueous media. The ability to conduct transformations, which have been limited to organic media, in water is essential for the further development of the important fields of green</p><p>catalysis and bioorthogonal chemistry, among other fields. In light of the recent progress in the expanding the scopes of reactions that can be conducted using nanoreactors, we aimed to gain deeper understanding of the roles of the hydrophobicity of both the core of micellar nanoreactors and the substrates on the reaction rates in water. Towards this goal we designed a set of metal-loaded micelles, composed of PEG-dendron amphiphiles and studied their ability to serve as nanoreactors for a palladium mediated depropargylation reaction of four substrates with different LogP values. Using dendrons as the hydrophobic block, allowed us to fine tune the lipophilicity of the dendritic end-groups and study how precise structural changes in the hydrophobicity of the amphiphiles affect the reaction rates. The kinetic data revealed linear relations between the rate constants and the hydrophobicity of the amphiphiles (estimated by the dendron’s</p><p>cLogP), while exponential dependence was obtained for the lipophilicity of the substrates (estimated by their LogP values). Our results demonstrate the vital contributions of the hydrophobicity of both the substrates and amphiphiles on the lipo-selectivity of nanoreactors, illustrating the potential of tuning hydrophobicity as a tool for optimizing</p><p>the reactivity and selectivity of nanoreactors.</p>

Evidence of protein coronas around soft nanoparticles regardless of the chemical nature of the outer surface: structural features and biological consequences

The presence of thick protein coronas has been found around pH-responsive polymeric assemblies. They reduce the levels of cellular uptake, nevertheless with positive outputs with regard to cytotoxic effects.

Intrinsic Effect of Pyridine-N-Position on Structural Properties of Cu-Based Low-Dimensional Coordination Frameworks

Metal-organic assemblies have received significant attention for catalytic and other applications, including gas and energy storage, due to their porosity and thermal/chemical stability. Here, we report the synthesis and physicochemical characterization of three metallosupramolecular assemblies consisting of isomeric ambidentate pyridyl-β-diketonate ligands L1–L3 and Cu(II) metal ions. It has been demonstrated that the topology and dimensionality of generated supramolecular aggregates depend on the location of the pyridine nitrogen donor atom in L1–L3. This is seen in characterization of two distinct 2D polymeric assemblies, i.e., [Cu(L1)2]n and [Cu(L2)2]n, in which both β-diketonate and pyridine groups are coordinated to the Cu(II) center, as well as in characterization of the mononuclear 1D complex Cu(L3)2, in which the central atom is bound only by two β-diketonate units.

A new fluorone-based bridging ligand for discrete and polymeric assemblies including Mo and W based [4+4] metallocycles

The synthesis of a planar, trianionic, redox-active ligand is described, which is able to bridge metal centres and form [4+4] square anionic metallocycles.

A general method to greatly enhance ultrasound-responsiveness for common polymeric assemblies

Ultrasound-controlled drug release is a very promising technique for controlled drug delivery due to the unique advantages of ultrasound as the stimulus.