BCC-Cu nanoparticles: from a transient to a stable allotrope by tuning size and reaction conditions.

Metallic copper generally adopts an FCC structure. In this work, we detect highly unusual BCC-structured Cu nanoparticles as a transient intermediate during the H reduction of a Cu precursor, [CuOBu], grafted onto the surface of partially dehydroxylated silica. The Cu BCC structure, assigned by Cu K-edge XANES and EXAFS, as well as synchrotron PXRD, converts upon heating into the most commonly found FCC allotrope.

Morpholine Ketene Aminal as Amide Enolate Surrogate in Iridium-Catalyzed Asymmetric Allylic Alkylation.

Morpholine ketene aminal is employed in iridium-catalyzed asymmetric allylic alkylation reactions as a surrogate for amide enolates to prepare γ,δ-unsaturated β-substituted morpholine amides. Kinetic resolution or, alternatively, stereospecific substitution affords the corresponding products in high enantiomeric excess. The utility of the products generated by this method has been showcased by their further elaboration into amines, ketones, or acyl silanes.

Selective Hydrogenation of CO to CH OH on Supported Cu Nanoparticles Promoted by Isolated Ti Surface Sites on SiO.

Small and narrowly distributed Cu nanoparticles, supported on SiO decorated with isolated Ti sites, prepared through surface organometallic chemistry, showed significantly improved CO hydrogenation activity and CH OH selectivity compared to the corresponding Cu nanoparticles supported on SiO . These isolated Lewis acid Ti sites, evidenced by UV/Vis spectroscopy, are proposed to stabilize surface intermediates at the interface between Cu nanoparticles and the support.