Alkyl initiated ring opening polymerization of lactide by indium complexes supported by NCN pincer ligands.

Indium-alkyl NCN pincer complexes supported by amine and imine donors are active catalysts for the ring opening polymerization of lactide. The amine indium complexes are significantly more active for polymerization due to the decoordination of the amine donors at higher temperatures. Solid state structures of the imine and amine indium complexes indicate that the imine-indium bonds are stronger than the analogous amine-indium bonds.

Cooperative Initiation in a Dinuclear Indium Complex for CO Epoxide Copolymerization.

Dinuclear indium complexes have been synthesized and characterized. These include neutral and cationic indium complexes supported by a Schiff base ligand bearing a binaphthol linker. The new compounds were investigated for alternating copolymerization of CO and cyclohexene oxide.

Impact of counterion valency on the rheology of sulfonated cellulose nanocrystal hydrogels.

A systematic rheological study on the influence of valency of different counterions on the properties of CNC hydrogels was carried out. Rheo-polarized microscopy was used to prove that preshear of 500 s for 1 min is adequate to completely breakdown agglomerates in the suspension. Furthermore, a rest period of 30 min is sufficient to recover the equilibrium structure of hydrogels.

Thermally stable zinc hydride catalyst for hydrosilylation of CO to silyl formate at atmospheric pressure.

Neutral zinc complexes supported by H[PNNO], a diaminophenolate ligand bearing a pendant phosphine group, were synthesized and characterized. The phosphine arm adopts two different configurations in solution and prevents aggregation. The monomeric zinc hydride complex is stable at elevated temperatures up to 125 °C and reacts readily with CO to afford a zinc formate complex.

Comparison of Imine- and Phosphinimine-Supported Indium Complexes: Tuning the Reactivity for the Sequential and Simultaneous Copolymerization of Lactide and ε-Caprolactone.

Imine- and phosphinimine-supported indium complexes were used as catalysts in the polymerization of racemic lactide and ε-caprolactone as well as their copolymerization by the sequential and simultaneous addition of monomers. Tuning the electronics and sterics of the indium centers by either (i) changing the nature of the nitrogen donors and (ii) coordinating a hemilabile side group had a significant effect on the reactivity of the complexes, their stability, and their control in the synthesis of block copolymers. Specifically, the imine-supported complex () showed the highest activity in the homo- and copolymerization of the cyclic esters, in contrast to the phosphinimine-supported complex (), which was significantly slower and less stable.

Indium-Catalyzed CO/Epoxide Copolymerization: Enhancing Reactivity with a Hemilabile Phosphine Donor.

Group 13 metal complexes have emerged as powerful catalysts for transforming CO into added-value products. However, direct comparisons of reactivity between Al, Ga, and In catalysts are rare. We report aluminum (), gallium (), and indium () complexes supported by a half-salen H[PNNO] ligand with a pendent phosphine donor and investigate their activity as catalysts for the copolymerization of CO and cyclohexene oxide.

Toward Biodegradable Electronics: Ionic Diodes Based on a Cellulose Nanocrystal-Agarose Hydrogel.

Bioderived cellulose nanocrystals (CNCs) are used to create light, flexible, biocompatible, and biodegradable electronic devices. Herein, surface modification of cellulose nanocrystals was employed to fabricate cationic and anionic CNCs. Subsequently, we demonstrated rectification behavior from a fixed junction between two agarose hydrogels doped with cationic and anionic cellulose nanocrystals.

Cationic indium catalysts for ring opening polymerization: tuning reactivity with hemilabile ligands.

This is a comprehensive study of the effects of rationally designed hemilabile ligands on the stability, reactivity, and change in catalytic behavior of indium complexes. We report cationic alkyl indium complexes supported by a family of hemi-salen type ligands bearing hemilabile thiophenyl (), furfuryl () and pyridyl () pendant donor arms. Shelf-life and stability of these complexes followed the trend < < , showing direct correlation to the affinity of the pendant donor group to the indium center.

Dinucleating Amino-Phenolate Platform for Zinc Catalysts: Impact on Lactide Polymerization.

We report imine- and amine-based dinucleating ligands bearing a bisphenol backbone and explore their coordination chemistry with zinc to form zinc alkyl, alkoxide, acetate, and amide complexes. Full characterization of the complexes shows that this ligand framework can support dinuclear and trinuclear complexes. We explore the reactivity of the zinc alkyl and alkoxide complexes as catalysts for the ring opening polymerization of lactide and compared this reactivity to analogous mononuclear complexes.

Catalytic activities of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol.

We report the catalytic properties of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol (4-CP). XRD, TEM, EDS, SAED, FTIR and BET were used to characterize the prepared material. Interaction between O3 and β-FeOOH was evident from the FTIR spectra.