峰值积分法的研究与应用

本文对峰值积分法（ＰＩＭＳ）的机理作了探讨，叙述了ＰＩＭＳ法应用于中低合金钢中不同状态铝：总铝（Ａｌｒ）、酸溶铝（Ａｌｓｏｌ）和酸不溶铝（Ａｌｉｎｓ）的成份测定，方法的精密度和准确度能满足分析的要求。     

A simple one-pot preparation of diazoacetoacetate derivatives from aldehydes

Diazoacetoacetate derivatives can be simply and efficiently prepared from aldehydes in a one-pot process involving initial DBU-promoted "aldol" condensation with ethyl diazoacetate followed by in situ oxidation with IBX. Aryl, alkyl, and unsaturated aldehydes are all viable substrates.     

Phosphinates as new electrophilic partners for cross-coupling reactions

The use of enol phosphinates as electrophiles for cross-coupling reactions has been explored. Both boronic acids (Suzuki-Miyaura reaction) and stannanes (Stille reaction) couple efficiently with lactam derived phosphinates.     

Selective optical control of electron spin coherence in singly charged GaAs-Al0.3Ga0.7As quantum dots

Coherent transient excitation of the spin ground states in singly charged quantum dots creates optically coupled and decoupled states of the electron spin. We demonstrate selective excitation from the spin ground states to the trion state through phase sensitive control of the spin coherence via these three states, leading to partial rotations of the spin vector. This progress lays the ground work for achieving complete ultrafast spin rotations.     

Chiral 1,2,4-triazoles: stereoselective acylation and chlorination

Acyl groups are transferred from diverse N- and O-acyl derivatives of chiral 3,5-bis-(1-hydroxyethyl)-[1,2,4]-triazole to amino acid esters enantioselectively, with 7% to 68% ee, depending on the temperature conditions and nature of the reagents. Thionyl chloride replaced the hydroxyl groups of (S)-1-[4-amino-5-((S)-1-hydroxy-ethyl)-[1,2,4]-triazol-3-yl]-ethanol 3 stereospecifically with inversion, as confirmed by X-ray analysis, which also revealed unusual crystal structures with asymmetric units comprising three molecules of 4-amino-3,5-bis(R-1-chloroethyl)-1,2,4-triazole 5 and four of 3,5-bis((R)-1-chloroethyl)-1H-1,2,4-triazole 6.     

A New Benzotriazole‐Mediated Stereoflexible Gateway to Hetero‐2,5‐diketopiperazines

Open chain Cbz‐L ‐aa¹‐L ‐Pro‐Bt (Bt=benzotriazole) sequences were converted into either the corresponding trans‐ or cis‐fused 2,5‐diketopiperazines (DKPs) depending on the reaction conditions. Thermodynamic tandem cyclization/epimerization afforded selectively the corresponding trans‐DKPs (69–75 %). Complementarily, tandem deprotection/cyclization led to the cis‐DKPs (65–72 %). A representative set of proline‐containing cis‐ and trans‐DKPs has been prepared. A mechanistic investigation, based on chiral HPLC, kinetics, and computational studies enabled a rationalization of the results.     

Density matrix tomography through sequential coherent optical rotations of an exciton qubit in a single quantum dot

We demonstrate single qubit density matrix tomography in a single semiconductor quantum dot system through consecutive phase sensitive rotations of the qubit via ultrafast coherent optical excitations. The result is important for quantifying gate operations in quantum information processing in the quantum dot systems as well as demonstrating consecutive arbitrary qubit rotations.     

Chiral heterocyclic ligands. XIV. Control of directionality in silver coordination polymers through ligand design

Four C(2)-symmetric homochiral ligands derived from (+)-camphor are shown to produce linear chain and ladder silver coordination polymers wherein the directionality and polarisation can be controlled by subtle differences in ligand design.