The LHCb Outer Tracker is a gaseous detector covering an area of 5x6 m2 with 12 double layers of straw tubes. The detector with its services are described together with the commissioning and ...calibration procedures. Based on data of the first LHC running period from 2010 to 2012, the performance of the readout electronics and the single hit resolution and efficiency are presented. The efficiency to detect a hit in the central half of the straw is estimated to be 99.2%, and the position resolution is determined to be approximately 200 um. The Outer Tracker received a dose in the hottest region corresponding to 0.12 C/cm, and no signs of gain deterioration or other ageing effects are observed.
Full conversion and enantioselectivities up to 83% have been obtained in the conjugate addition reactions of diethyl zinc to Michael acceptors catalyzed by well-defined (chiral) copper(I) ...aminoarenethiolates. Interesting differences between organozinc or Grignard reagents have been found: for cyclic enones R2Zn reagents afford better results, whereas earlier work showed that RMgX reagents react more selectively with acyclic enones.
Aryllithium compounds LiC6H4(CH2N(Et)CH2CH2NEt2)-22 (2b), LiC6H4(CH(Me)N(Me)CH2CH2NMe2-(R))-22 ((R)-3b), and LiC6H4(CH(Me)N(Me)CH2CH2NMe2-(rac))-22 ((rac)-3b) were synthesized and characterized in ...the solid state and in solution. X-ray crystallographic studies of 2b and (R)-3b and molecular weight determinations of 2b, (R)-3b, and (rac)-3b by cryoscopy in benzene showed that, both in the solid state and in apolar, noncoordinating solvents such as benzene, these compounds exist as discrete dimeric aggregates. For (R)-3b and (rac)-3b the aggregation process of two monomeric aryllithium units to one dimer is highly diastereoselective.
The attachment of an aminoarenethiolato copper(I) catalyst to a carbosilane dendritic wedge is described. This new catalyst is comparable in activity for the 1,4-addition of diethylzinc to ...2-cyclohexenone as the parent catalyst but more robust. In addition, the new catalytic material can be easily recovered by dialysis from the reaction products and subsequently reused.
An aminoarenethiolato copper(I) catalyst was attached to a carbosilane dendritic wedge, which had been prepared via a novel convergent synthetic method. Compared with the unsupported complex, this novel dendritic copper(I) catalyst is more robust towards hydrolysis and oxidation and has increased solubility in common organic solvents. The catalytic activity of the dendritic copper catalyst was tested in the 1,4-addition of Et
2Zn to 2-cyclohexenone. In both polar (Et
2O) and apolar (hexane) solvents excellent activity was observed. The fact that the catalytic copper site remains attached to the nanosize dendritic aminoarenethiolate ligand allows separation of this catalyst by means of nanofiltration.
PDF
