This work applies organometallic routes to copper(0/I) nanoparticles and describes how to match ligand chemistries with different material compositions. The syntheses involve reacting an organo‐copper precursor, mesitylcopper(I) [CuMes]z (z=4, 5), at low temperatures and in organic solvents, with hydrogen, air or hydrogen sulfide to deliver Cu, Cu2O or Cu2S nanoparticles. Use of sub‐stoichiometric quantities of protonated ligand (pro‐ligand; 0.1–0.2 equivalents vs. [CuMes]z) allows saturation of surface coordination sites but avoids excess pro‐ligand contaminating the nanoparticle solutions. The pro‐ligands are nonanoic acid (HO2CR1), 2‐[2‐(2‐methoxyethoxy)ethoxy]acetic acid (HO2CR2) or di(thio)nonanoic acid, (HS2CR1), and are matched to the metallic, oxide or sulfide nanoparticles. Ligand exchange reactions reveal that copper(0) nanoparticles may be coordinated by carboxylate or di(thio)carboxylate ligands, but Cu2O is preferentially coordinated by carboxylate ligands and Cu2S by di(thio)carboxylate ligands. This work highlights the opportunities for organometallic routes to well‐defined nanoparticles and the need for appropriate ligand selection.
Thermoplastic elastomers based on polyesters/carbonates have the potential to maximize recyclability, degradability and renewable resource use. However, they often underperform and suffer from the familiar trade‐off between strength and extensibility. Herein, we report well‐defined reprocessable poly(ester‐b‐carbonate‐b‐ester) elastomers with impressive tensile strengths (60 MPa), elasticity (>800 %) and recovery (95 %). Plus, the ester/carbonate linkages are fully degradable and enable chemical recycling. The superior performances are attributed to three features: (1) Highly entangled soft segments; (2) Fully reversible strain‐induced crystallization and (3) Precisely placed ZnII‐carboxylates dynamically crosslinking the hard domains. The one‐pot synthesis couples controlled cyclic monomer ring‐opening polymerization and alternating epoxide/anhydride ring‐opening copolymerization. Efficient convresion to ionomers is achieved by reacting vinyl‐epoxides to install ZnII‐carboxylates.
Chiral, PAH substituted N,C-chelate boron compounds are systematically investigated to establish the effect of triplet energy and substitution position on their photoreactivity. They all undergo regioselective photoisomerization, forming new dark isomers with quantum efficiencies reflecting these various factors. New PAH fused 4bH-azaborepins are obtained via thermal isomerization of the dark isomers. These results further implicate a photoactive triplet state in the photoisomerization process and its utility in achieving rare PAH-fused azaborepin-like heterocycles.
Thermoplastic elastomers based on polyesters/carbonates have the potential to maximize recyclability, degradability and renewable resource use. However, they often underperform and suffer from the familiar trade‐off between strength and extensibility. Herein, we report well‐defined reprocessable poly(ester‐b‐carbonate‐b‐ester) elastomers with impressive tensile strengths (60 MPa), elasticity (>800 %) and recovery (95 %). Plus, the ester/carbonate linkages are fully degradable and enable chemical recycling. The superior performances are attributed to three features: (1) Highly entangled soft segments; (2) Fully reversible strain‐induced crystallization and (3) Precisely placed ZnII‐carboxylates dynamically crosslinking the hard domains. The one‐pot synthesis couples controlled cyclic monomer ring‐opening polymerization and alternating epoxide/anhydride ring‐opening copolymerization. Efficient convresion to ionomers is achieved by reacting vinyl‐epoxides to install ZnII‐carboxylates.
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