Measurement of Transverse Single-Spin Asymmetries for Mid-rapidity Production of Neutral Pions and Charged Hadrons in Polarized p+p Collisions at sqrt(s) = 200 GeV

The transverse single-spin asymmetries of neutral pions and non-identified charged hadrons have been measured at mid-rapidity in polarized proton-proton collisions at sqrt(s) = 200 GeV. The data cover a transverse momentum (p_T) range 0.5-5.0 GeV/c for charged hadrons and 1.0-5.0 GeV/c for neutral pions, at a Feynman-x (x_F) value of approximately zero. The asymmetries seen in this previously unexplored kinematic region are consistent with zero within statistical errors of a few percent. In addition, the inclusive charged hadron cross section at mid-rapidity from 0.5 < p_T < 7.0 GeV/c is presented and compared to NLO pQCD calculations. Successful description of the unpolarized cross section above ~2 GeV/c using NLO pQCD suggests that pQCD is applicable in the interpretation of the asymmetry results in the relevant kinematic range.Comment: 331 authors, 6 pages text, 2 figures, 3 tables. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV

The momentum distribution of electrons from semi-leptonic decays of charm and bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative quantum chromodynamics (pQCD) calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is \sigma_{b\b^bar}= 3.2 ^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Saturation of azimuthal anisotropy in Au + Au collisions at sqrt(s_NN) = 62 - 200 GeV

New measurements are presented for charged hadron azimuthal correlations at mid-rapidity in Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. They are compared to earlier measurements obtained at sqrt(s_NN) = 130 GeV and in Pb+Pb collisions at sqrt(s_NN) = 17.2 GeV. Sizeable anisotropies are observed with centrality and transverse momentum (p_T) dependence characteristic of elliptic flow (v_2). For a broad range of centralities, the observed magnitudes and trends of the differential anisotropy, v_2(p_T), change very little over the collision energy range sqrt(s_NN) = 62-200 GeV, indicating saturation of the excitation function for v_2 at these energies. Such a saturation may be indicative of the dominance of a very soft equation of state for sqrt(s_NN) = 62-200 GeV.Comment: 432 authors, 7 pages text, 4 figures, REVTeX4. To be submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Asymmetric Michael reaction of diethyl malonate with crotonaldehyde catalyzed by chiral aminocarboxylates, amino alcoholates, and amino phenolates

Alkali metal salts of substituted (S)-prolines, alkali metal alkoxides of (S)-prolinol, and Na salts of chiral substituted 2-amino-2'-hydroxy-1,1'-binaphthyls can catalyze the asymmetric Michael reaction of diethyl malonate with crotonaldehyde to give adducts in >90% yields with ee up to 40%. The influences of the catalyst structure, the nature of the alkali metal cation, temperature, the solvent, and salt additives on the reaction outcome were studied.

When Applying the Mercury Poisoning Test to Palladacycle-Catalyzed Reactions, One Should Not Consider the Common Misconception of Mercury(0) Selectivity

The aim of this study was to demonstrate the absolute necessity of control experiments for a correct interpretation of mercury drop test results when applied to mechanistic studies of palladacycle-catalyzed reactions. It was shown that the interaction of diverse azapalladacycles with metallic mercury leads to the formation of organomercuric chlorides during the redox-transmetalation process. The structure of these organomercurials was confirmed by elemental analysis, 1H, 13C{1H}, and 199Hg{1H} NMR spectra, X-ray diffraction analysis, and DFT calculations. The behavior and properties of C,N-mercuracycles bearing the weak and labile N···Hg bond are discussed on the basis of the temperature dependence of the NMR spectra and calculated thermodynamic parameters of the dechelation process. © 2018 American Chemical Society

Determination of the Absolute Configuration of CN-Palladacycles by 31P{1H} NMR Spectroscopy Using (1R,2S,5R)-Menthyloxydiphenylphosphine as the Chiral Derivatizing Agent: Efficient Chirality Transfer in Phosphinite Adducts

A series of (1R)-MenOPPh2 phosphinite derivatives of α-arylalkylaminate CN-palladacycles of known absolute configuration was prepared. Their structure and stereochemistry were determined using different experimental (NMR spectroscopy and X-ray diffraction) and theoretical (density functional theory calculation) methods. Despite the conformational mobility of the phosphinite reagent and the highly remote position of its stereocenters from those of the cyclopalladated amine, efficient chirality transfer in the phosphinite cyclopalladated complexes was established. On the basis of these results, a new method for the determination of the absolute configuration of chiral CN-palladacycles was elaborated using the (1R)-MenOPPh2 phosphinite as a highly sensitive referee ligand and in situ 31P{1H} NMR spectroscopy as a control method. The proposed approach is a remarkable addition to the classical NMR techniques, increasing their versatility and excluding the isolation of the phosphinite derivatives. © 2016 American Chemical Society