Synthesis of Chiral Diamine Ligands for Nickel-catalyzed Asymmetric Cross-couplings of Alkylchloroboronate Esters with Alkylzincs: (1R,2R)-N,N’-Dimethyl-1,2-bis(2-methylphenyl)-1,2-diaminoethane

A. (1R,2R)-N,N'-Bis(2-hydroxyphenylmethylene)-1,2-bis(2-methylphenyl)-1,2-diaminoethane (1). An oven-dried, 100-mL, two-necked, round-bottomed flask equipped with a magnetic stir bar (13 × 9 mm, octagon-type), a rubber septum, and a nitrogen line is evacuated under high vacuum (1.0 mmHg) and filled with nitrogen (three cycles). (1S,2S)-1,2-Bis(2-hydroxyphenyl)-1,2-diaminoethane (1.0 g, 4.1 mmol, 1.0 equiv) (Note 2) is added through the open neck under a positive pressure of nitrogen. The open neck is capped with a rubber septum, and then anhydrous DMSO (20 mL) (Note 3) and 2-methylbenzaldehyde (1.23 g, 10.2 mmol, 2.5 equiv) (Note 4) are added into the flask by syringe through the rubber septum. After the yellow solution (Figure 1) is stirred for 14 h at 20 °C, the reaction is quenched by the addition of distilled water (100 mL), and the mixture is extracted with Et₂O (20 mL × 3). The combined organic layer is washed with water (30 mL) and a saturated aqueous solution of NaCl (30 mL), dried over anhydrous Na₂SO₄ (5 g), filtered through filter paper, and concentrated by rotary evaporation (30 mmHg, 30 °C) and under vacuum (1.0 mmHg). The product, obtained as a yellow oil as a mixture with unreacted 2-methylbenzaldehyde, is used in the next step without further purification (2.2 g, ~98% yield) (Note 5)

Manifolds associated with (Z2)n(Z_2)^n-colored regular graphs

In this article we describe a canonical way to expand a certain kind of $(\mathbb Z_2)^{n+1}$-colored regular graphs into closed $n$-manifolds by adding cells determined by the edge-colorings inductively. We show that every closed combinatorial $n$-manifold can be obtained in this way. When $n\leq 3$, we give simple equivalent conditions for a colored graph to admit an expansion. In addition, we show that if a $(\mathbb Z_2)^{n+1}$-colored regular graph admits an $n$-skeletal expansion, then it is realizable as the moment graph of an $(n+1)$-dimensional closed $(\mathbb Z_2)^{n+1}$-manifold.Comment: 20 pages with 9 figures, in AMS-LaTex, v4 added a new section on reconstructing a space with a $(Z_2)^n$-action for which its moment graph is a given colored grap

Analysis of scale-free networks based on a threshold graph with intrinsic vertex weights

Many real networks are complex and have power-law vertex degree distribution, short diameter, and high clustering. We analyze the network model based on thresholding of the summed vertex weights, which belongs to the class of networks proposed by Caldarelli et al. (2002). Power-law degree distributions, particularly with the dynamically stable scaling exponent 2, realistic clustering, and short path lengths are produced for many types of weight distributions. Thresholding mechanisms can underlie a family of real complex networks that is characterized by cooperativeness and the baseline scaling exponent 2. It contrasts with the class of growth models with preferential attachment, which is marked by competitiveness and baseline scaling exponent 3.Comment: 5 figure

The Role of Mindfulness and Psychological Flexibility in Somatization, Depression, Anxiety, and General Psychological Distress of a Non-clinical College Sample

The current study investigated whether mindfulness and psychological flexibility uniquely and separately accounted for variability in psychological distress (somatization, depression, anxiety, and general psychological distress). An ethnically diverse, non-clinical sample of college undergraduates (N = 494, 76% female) completed a web-based survey that included the self-report measures of interest. Consistent with prior research, psychological flexibility and mindfulness were positively associated with each other, and tested separately, both variables were negatively associated with somatization, depression, anxiety, and general psychological distress. Results also revealed that psychological flexibility and mindfulness accounted for unique variance in all four measures of distress. These findings suggest that mindfulness and psychological flexibility are interrelated but not redundant constructs, and that both constructs are important for understanding the onset and maintenance of somatization, depression, anxiety, and general distress

Synthesis of Chiral Diamine Ligands for Nickel-catalyzed Asymmetric Cross-couplings of Alkylchloroboronate Esters with Alkylzincs: (1R,2R)-N,N’-Dimethyl-1,2-bis(2-methylphenyl)-1,2-diaminoethane

A. (1R,2R)-N,N'-Bis(2-hydroxyphenylmethylene)-1,2-bis(2-methylphenyl)-1,2-diaminoethane (1). An oven-dried, 100-mL, two-necked, round-bottomed flask equipped with a magnetic stir bar (13 × 9 mm, octagon-type), a rubber septum, and a nitrogen line is evacuated under high vacuum (1.0 mmHg) and filled with nitrogen (three cycles). (1S,2S)-1,2-Bis(2-hydroxyphenyl)-1,2-diaminoethane (1.0 g, 4.1 mmol, 1.0 equiv) (Note 2) is added through the open neck under a positive pressure of nitrogen. The open neck is capped with a rubber septum, and then anhydrous DMSO (20 mL) (Note 3) and 2-methylbenzaldehyde (1.23 g, 10.2 mmol, 2.5 equiv) (Note 4) are added into the flask by syringe through the rubber septum. After the yellow solution (Figure 1) is stirred for 14 h at 20 °C, the reaction is quenched by the addition of distilled water (100 mL), and the mixture is extracted with Et₂O (20 mL × 3). The combined organic layer is washed with water (30 mL) and a saturated aqueous solution of NaCl (30 mL), dried over anhydrous Na₂SO₄ (5 g), filtered through filter paper, and concentrated by rotary evaporation (30 mmHg, 30 °C) and under vacuum (1.0 mmHg). The product, obtained as a yellow oil as a mixture with unreacted 2-methylbenzaldehyde, is used in the next step without further purification (2.2 g, ~98% yield) (Note 5)

Macroscopic and Local Magnetic Moments in Si-doped CuGeO3_3 with Neutron and μ\muSR Studies

The temperature-concentration phase diagram of the Si-doped spin-Peierls compound CuGeO$_{3}$ is investigated by means of neutron scattering and muon spin rotation spectroscopy in order to determine the microscopic distribution of the magnetic and lattice dimerised regions as a function of doping. The analysis of the zero-field muon spectra has confirmed the spatial inhomogeneity of the staggered magnetisation that characterises the antiferromagnetic superlattice peaks observed with neutrons. In addition, the variation of the macroscopic order parameter with doping can be understood by considering the evolution of the local magnetic moment as well as of the various regions contributing to the muon signal

Reentrant Spin-Peierls Transition in Mg-Doped CuGeO_3

We report a synchrotron x-ray scattering study of the diluted spin-Peierls (SP) material Cu_{1-x}Mg_xGeO_3. In a recent paper we have shown that the SP dimerization attains long-range order only for x < x_c = 0.022(0.001). Here we report that the SP transition is reentrant in the vicinity of the critical concentration x_c. This is manifested by broadening of the SP dimerization superlattice peaks below the reentrance temperature, T_r, which may mean either the complete loss of the long-range SP order or the development of a short-range ordered component within the long-range ordered SP state. Marked hysteresis and very large relaxation times are found in the samples with Mg concentrations in the vicinity of x_c. The reentrant transition is likely related to the competing Neel transition which occurs at a temperature similar to T_r. We argue that impurity-induced competing interchain interactions play an essential role in these phenomena.Comment: 5 pages, 4 embedded eps figure