Sungwoo Yoon

Facile synthesis of uniform large-sized InP nanocrystal quantum dots using tris(tert-butyldimethylsilyl)phosphine.

Colloidal III-V semiconductor nanocrystal quantum dots [NQDs] have attracted interest because they have reduced toxicity compared with II-VI compounds. However, the study and application of III-V semiconductor nanocrystals are limited by difficulties in their synthesis. In particular, it is difficult to control nucleation because the molecular bonds in III-V semiconductors are highly covalent. A synthetic approach of InP NQDs was presented using newly synthesized organometallic phosphorus [P] precursors with different functional moieties while preserving the P-Si bond. Introducing bulky side chains in our study improved the stability while facilitating InP formation with strong confinement at a readily low temperature regime (210°C to 300°C). Further shell coating with ZnS resulted in highly luminescent core-shell materials. The design and synthesis of P precursors for high-quality InP NQDs were conducted for the first time, and we were able to control the nucleation by varying the reactivity of P precursors, therefore achieving uniform large-sized InP NQDs. This opens the way for the large-scale production of high-quality Cd-free nanocrystal quantum dots.

Mukaiyama Aldol Reactions Catalyzed by a Trimeric Organo Aluminum(III) Alkoxide

Abstract Mukaiyama aldol reactions of enol ethers with a variety of aldehydes and ketones are efficiently catalyzed at 0–25 °C by the sterically bulky trimeric organo aluminum(III) alkoxide 1 synthesized via the reaction of 3 equiv of AlMe3 with tripodal tris(2-hydroxy-3-tert-butyl-5-methylphenyl) methane and the elimination of 3 equiv of methane. Comparisons of its catalytic properties with the less sterically hindered analogue 2, the more sterically hindered analogue 3, a monomeric aluminum near-analogue 4, and a dimeric alumatrane 5 revealed that 1 possesses superior activity. GRAPHICAL ABSTRACT

2-Benzhydryl-6-tert-butyl-4-methyl-phenol.

The title compound, C24H26O, was prepared by the reaction between 2-tert-butyl-4-methylphenol and diphenylmethanol in the presence of sulfuric acid. Three benzene rings are attached directly to the central C—H group in a twisted propeller conformation with the local pseudo-C 3 rotational axis coinciding with the C—H bond. There are three short C—H⋯O contacts in the molecule.