Photochemical properties and shape evolution of CdSe QDs in a non-injection reaction.

Highly monodispersed CdSe quantum dots (QDs) were prepared without an injection procedure. A series of Cd salts of long chain fatty acids, including Cd-myristate (C14), Cd-palmitate (C16) and Cd-stearate (C18) was prepared, and all metallic precursors and surfactants were mixed together followed by increasing the temperature in a controlled manner. The reaction resulted in highly monodisperse and bright zinc blende QDs. In addition, the effects of specific ligands which have been known to lead anisotropic growth of the nanocrystals in the injection method were investigated. The use of alkyl phosphonic acid and alkyl amine was found to produce extremely monodisperse CdSe QDs with a high quantum yield. This procedure was proven to be able to yield a large quantity of zinc blende CdSe QDs (2 g) in a one-pot reaction. The use of a controlled amount of tetradecylphosphonic acid and octadecylamine resulted in tetrapod- and match-shaped QDs, the first reported by a non-injection method. These results clearly demonstrate that appropriate combination of precursors can provide high quality of CdSe nanocrystals in terms of quantum yield, monodispersity and shape control by a non-injection method.

2-[(1H-Pyrrol-2-yl)meth-yl]-1H-pyrrole.

In the title compound, C9H10N2, the two pyrrole ring planes are twisted by a dihedral angle of 69.07 (16)° and the C-C-C methane angle is 115.1 (2)°. In the crystal, mol-ecules are connected into layers in the bc plane by N-H⋯π inter-actions.

Methyl 6-dimethyl-amino-4-hy-droxy-2-naphtho-ate.

In the title compound, C(14)H(15)NO(3), the ester group is oriented so that the carbonyl group points in the opposite direction to the hy-droxy group. The mol-ecule as a whole is almost planar (the r.m.s. deviation of the non-H atoms is 0.0268 Å). In the crystal, mol-ecules are linked by inter-molecular O-H⋯O hydrogen bonds into infinite chains that propagate parallel to the c axis.

Lipase mediated chiral resolution of 4-arylthio-2-butanol as an intermediate for beta-lactam antibiotics.

This paper deals with chiral enzymatic resolution of 4-arylthio-2-butanols by lipase to prepare potential intermediates of beta-lactam antibiotics. Among several lipases employed, lipase P type enzyme gave the highest ee value to prepare (R)-4-arylthio-2-butyl acetate. The enzymatic resolution of phenyl substituted alcohol (6a) using lipase P showed the highest ee value (99.7%) among those of 4-arylthio-2-butanol derivatives. Lipase P mediated hydrolysis of acylester 7a gave also (R)-alcohol 6a selectively. For determination of enantiomeric purity of these enzymatic resolved analytes, liquid chromatographic analysis was performed using two coupled Chiralcel OD and (R,R)-WhelkO chiral column.