Smart yolk-shell nanoparticles (hollow nanoparticles with a movable core) with an acidic shell and a basic core were fabricated through an organosilane-assisted selective etching method and acted as efficient nanoreactors for catalyzing a deacetalization-Henry cascade reaction with high activity and high selectivity. This strategy is very promising for the design of multifunctional nanoreactors for cascade reactions.

No abstract

The crystalline and magnetic structures of the YCo 3 -H͑D͒ system have been investigated by means of x-ray and neutron diffraction with the objective of understanding the complex magnetic changes that are observed in this system as hydrogen is added. Synchrotron x-ray diffraction ͑XRD͒ patterns were first refined to yield the lattice parameters and coordination of Y and Co atoms in the metal and two ␤-hydride phases while XRD was used for the ␥ phase. In situ neutron powder diffraction measurements of YCo 3 D x were then made in all four phases to determine the deuterium site occupancies and magnetic structures. The site occupancies were also rationalized using the Westlake geometric model. The highest hydrogen concentration measured was YCo 3 H 4.6 . Using the Westlake model, we conclude that the saturated hydrogen content would be YCo 3 H 5 . Our results reported here and in Part I ͓Phys. Rev. B 76, 184443 ͑2007͔͒ have enabled us to rationalize the changes in the magnetic structures in terms of changes in the cobalt-cobalt distance caused by the addition of hydrogen. In particular, in the antiferromagnetic ␥ phase, we observe Co atomic displacements that enable the structure to adopt a particular antiferromagnetic structure in a manner that is reminiscent of a Peierls distortion as observed in transitions from the conducting to nonconducting hydrides on addition of hydrogen in YH 3 .

Substitutional heterovalent doping represents an effective method to control the optical and electronic properties of nanocrystals (NCs). Highly monodisperse II-VI NCs with deep substitutional dopants are presented. The NCs exhibit stable, dominant, and strong dopant fluorescence, and control over n- and p-type electronic impurities is achieved. Large-scale, bottom-up superlattices of the NCs will speed up their application in electronic devices.