Clean and green: Copper(I) complexes of phenanthroline‐based ligands anchored on the chitosan polymer are good catalysts for the “click” cycloaddition of azides with terminal alkynes (see scheme; the scanning electron microscopy image shows the porous structure of the catalyst). These heterogeneous catalytic systems do not require a base or reducing agent and operate in alcohol or water.
A series of bimetallic [(NHC)PtX2]2(diamine) complexes have been prepared as a new chemotype for potential anticancer agents. These complexes display an uncommon set of structural features as far as they combine two bifunctional, trans-configured platinum centers. They display cytotoxic activities in the micromolar range on many cancerous cell lines and do not cross-react with cisplatin in A2780/DDP cell lines. They bind slowly to double-stranded DNAs, giving monoadducts as the major products. Pathways for cellular toxicity have been investigated for both mono- and bimetallic trans-(NHC)PtX2(amine) complexes. It has been highlighted that, unlike cisplatin, these complexes do not induce cell cycle arrest. They trigger apoptosis in A2780 cells by a pathway involving translocation of apoptosis-inducing factor and caspase 12 to the nucleus. Moreover, bimetallic complexes may induce necrosis.
This work describes the preparation and characterization
of a library of alginate-supported palladium nanoparticles together
with their catalytic capabilities to promote the Suzuki–Miyaura
reaction. Using the chelating properties of the carboxylate functions
of the alginate matrix a series of Ca, Ba, Mn, Zn, Ni, Ce, Cu, and
Co alginate gels were first prepared and then reacted with Pd2+ salts. Partial exchange of metal cations followed by Pd
reduction into palladium nanoparticles and supercritical CO2 drying generated a panel of bimetallic alginate aerogels. Physical
characterizations of these materials showed a significant influence
of both the gelling metal nature and the Pd loading on surface areas
and nanoparticles size. A comparative study of the catalytic performances
of these heterogeneous catalytic systems is then reported for the
Suzuki–Miyaura reaction. This study highlighted the superior
performances of palladium nanoparticles supported on copper-alginate
aerogels. This heterogeneous catalyst showed high catalytic activities
as illustrated by a TOF value of 10 s–1 and a TON
value close to 106. The robustness of the catalyst allowed
several reuses with no significant loss of activity or metal leaching.
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