Showing papers in "Journal of The Chemical Society, Chemical Communications in 1999"

Recent advances in the preparation of semiconductors as isolated nanometric particles: new routes to quantum dots

Abstract: Nanoparticles of semiconductor materials have been the subject of intense research in the last five years owing to the novel electronic, catalytical and optical properties observed in such materials. The unusual properties of these so called quantum dots can be attributed to two main factors: the large surface to volume ratio of atoms and the confinement of charge carriers in a ‘quantum mechanical box’. Small particles of semiconductors have been prepared by a number of routes, often using colloidal chemistry methods but more recently using organometallic routes. The recent advances have resulted in high quality nanoparticles which have been incorporated into simple devices. In this article we cover some of the key advances in the preparation of nanometric particles of semiconductors. The cover illustration depicts three sizes of TOPO capped CdSe.

Functional analysis of phenylalanine 365 in hopene synthase, a conserved amino acid in the families of squalene and oxidosqualene cyclases

Abstract: Two bicyclic products were accumulated by the mutant F365A, showing the amino acid residue is located close to the transient C-8 carbocation intermediate in the active site cavity; the mutants of F365Y and F365W significantly accelerated the cyclization reaction at low temperatures.

syn- and anti-Benzotris(norbornadiene)s.

Abstract: The hitherto unknown syn and anti isomers of benzotris(norbornadiene) 7, the only molecules that include both features known to lead to bond length alternation in benzenes, i.e. bicyclic ring strain and π–π interaction, have been synthesized from 2,3-dibromonorbornadiene using butyllithium and copper(I) iodide.

Resonance Raman evidence for the interconversion between an [FeIII–η1-OOH]2+ and [FeIII–η2-O2]+ species and mechanistic implications thereof

Abstract: The deprotonation of [FeIII(N4Py)(η1-OOH)]2+ 1 gives [FeIII(N4Py)(η2-OO)]+ 2, as unequivocally demonstrated by resonance Raman spectroscopy, and leads to the loss of alkane hydroxylation activity by 1.

An unusual matrix of stereocomplementarity in the hydroxylation of monohydroxy fatty acids catalysed by cytochrome P 450 from Bacillus megaterium with potential application in biotransformations

Abstract: Cytochrome P450 from Bacillus megaterium catalyses the diastereoselective hydroxylations of 13-hydroxymyristic acid, to predominantly erythro-12,13-dihydroxymyristic acid, and of 12-hydroxymyristic acid to give predominantly threo-12,13-dihydroxymyristic acid, in reactions that are stereocomplementary and with considerable potential application in biotransformations.