A green route towards substituted 2-amino-4H-chromenes catalyzed by an organobase (TBD) functionalized mesoporous silica nanoparticle without heating

Research on Chemical Intermediates - 1,5,7-Triazabicyclo-[4,4,0]-dec-1-ene functionalized mesoporous silica nanoparticle promoted one-pot multicomponent synthesis of 2-amino-4H-chromenes from a...     

Synthesis,X-ray crystal structure,DFT calculations,spectroscopic characterization and redox behaviour of a rhodium(III) complex of an anthracene–pyridylhydrazone ligand

Transition Metal Chemistry - A pyridylhydrazone incorporating an anthracene moiety, designated as HLAnc, has been synthesized in order to examine its coordination behaviour towards rhodium(III)....     

Identification of metabolites in coriander seeds (Coriandrum Sativum L.) aided by ultrahigh resolution total correlation NMR spectroscopy

NMR is a fast method for obtaining a holistic snapshot of the metabolome and also offers quantitative information without separating the compounds present in a complex mixture. Identification of the metabolites present in a plant extract sample is a crucial step for all plant metabolomics studies. In the present work, we used various two dimensional (2D) NMR methods such as J-resolved NMR, total correlation spectroscopy (TOCSY), and heteronuclear single quantum coherence sensitivity enhanced NMR spectroscopy for the identification of 36 common metabolites present in Coriandrum sativum L. seed extract. The identified metabolites belong to the following classes: organic acids, amino acids, and carbohydrates. ¹H NMR spectra of such complex mixtures in general display tremendous signal overlap due to the presence of a large number of metabolites with closely resonating multiplet signals. This signal overlapping leads to ambiguity in an assignment, and hence, identification of metabolites becomes tedious or impossible in many cases. Therefore, the utility of pure-shift proton spectrum along the indirect (F₁) dimension of the F₁-PSYCHE-TOCSY spectrum is demonstrated for overcoming ambiguity in assignment of metabolites in crowded spectral regions from Coriandrum sativum L. seed extract sample. Because pure-shift NMR methods yield ultrahigh resolution spectrum (i.e., a singlet peak per chemical site) along one or more dimensions, such spectra provide better identification of metabolites compared with regular 2D TOCSY where signal overlap and peak distortions lead to ambiguity in the assignment. Nine metabolites were unambiguously assigned by pure-shift F₁-PSYCHE-TOCSY spectrum, which was unresolved in regular TOCSY spectrum.     

All-optical method of developing a phase encoded latch by using EDFA

Optics has already proved its meaningful application in information processing and computation, where the parallelism of light is exploited to achieve the desired result. In this communication a novel concept of all-optical memory unit based on phase encoding process is proposed. The unit is simple in architecture comprising phase sifters, mirrors (M′) and two blocks of Erbium doped fiber amplifier. The optical feedback is supported by use of beam splitters and mirrors. It is independent of intensity and therefore requires a small switching power and can work at a bit rate far above 100 Gb/s.     

A competent pot and atom-efficient synthesis of Betti bases over nanocrystalline MgO involving a modified Mannich type reaction

A simple, efficient, and eco-friendly method for the synthesis of 1-(α-aminoalkyl) naphthols, the Betti bases, has been carried out over a basic nanocrystalline MgO catalyst in aqueous condition. The method has been applied for the synthesis of a range of compounds with variable functionalities in excellent yield and selectivity.     

Effect of spin–orbit coupling on spin transport at graphene/transition metal interface

In spite of large spin coherence length in graphene due to small spin–orbit coupling, the created potential barrier and antiferromagnetic coupling at graphene/transition metal (TM) contacts strongly reduce the spin transport behavior in graphene. Keeping these critical issues in mind in the present work, ferromagnetic (Co, Ni) nanosheets are grown on graphene surface to elucidate the nature of interaction at the graphene/ferromagnetic interface to improve the spin transistor characteristics. Temperature dependent magnetoconductance shows unusual behavior exhibiting giant enhancement in magnetoconductance with increasing temperature. A model based on spin–orbit coupling operated at the graphene/TM interface is proposed to explain this anomalous result. We believe that the device performance can be improved remarkably tuning the spin–orbit coupling at the interface of graphene based spin transistor. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Activation of Nucleotide-Binding Oligomerization Domain 1 (NOD1) Receptor Signaling in Labeo rohita by iE-DAP and Identification of Ligand-Binding Key Motifs in NOD1 by Molecular Modeling and Docking

The nucleotide-binding oligomerization domain 1 (NOD1) receptor recognizes various pattern-associated structures of microbes through its leucine-rich repeat (LRR) domain and activates signaling cascades to induce innate immunity. This report describes the activation of NOD1 receptor signaling by gamma-d-glutamyl-meso-diaminopimelic acid (or γ-D-Glu-mDAP [iE-DAP]) in a commercially important fish species, rohu (Labeo rohita). It also described critical motifs in the NOD1-LRR domain that could be involved in binding iE-DAP, lipopolysaccharide (LPS), and polyinosinic:polycytidylic acid (poly I:C). The activation of NOD1 receptor signaling was studied by injecting iE-DAP, and analysis of tissue samples for NOD1 and receptor-interacting serine/threonine kinase (RICK) expression was done by quantitative real-time polymerase chain reaction (qRT-PCR) assay. To identify ligand-binding motifs in NOD1, the 3D model of NOD1-LRR was generated, followed by a 6-ns molecular dynamics simulation. Molecular docking of LPS with NOD1-LRR was executed at the Hex and PatchDock servers, and iE-DAP and poly I:C in the AutoDock 4.2, FlexX 2.1, Glide 5.5, and GOLD 4.1 programs. The results of qRT-PCR revealed significant (p?<?0.05) upregulation of NOD1 and RICK expression. Molecular docking revealed that the amino acid residues at LRR1–2, LRR3–7, and LRR8–9 could be involved in poly I:C, LPS, and iE-DAP binding, respectively. In fish, this is the first report describing the 3D structure of NOD1-LRR and its critical ligand-binding motifs.     

Unexpected Macrocyclic Multinuclear Zinc and Nickel Complexes that Function as Multitasking Catalysts for CO2 Fixations

Unique self‐assembled macrocyclic multinuclear Zn^II and Ni^II complexes with binaphthyl‐bipyridyl ligands (L) were synthesized. X‐ray analysis revealed that these complexes consisted of an outer ring (Zn₃L₃ or Ni₃L₃) and an inner core (Zn₂ or Ni). In the Zn^II complex, the inner Zn₂ part rotated rapidly inside the outer ring in solution on an NMR timescale. These complexes exhibited dual catalytic activities for CO₂ fixations: synthesis of cyclic carbonates from epoxides and CO₂ and temperature‐switched N‐formylation/N‐methylation of amines with CO₂ and hydrosilane.     

Effects of partial slip,viscous dissipation and Joule heating on Von Kármán flow and heat transfer of an electrically conducting non-Newtonian fluid

The steady Von Kármán flow and heat transfer of an electrically conducting non-Newtonian fluid is extended to the case where the disk surface admits partial slip. The fluid is subjected to an external uniform magnetic field perpendicular to the plane of the disk. The constitutive equation of the non-Newtonian fluid is modeled by that for a Reiner–Rivlin fluid. The momentum equations give rise to highly non-linear boundary value problem. Numerical solutions for the governing non-linear equations are obtained over the entire range of the physical parameters. The effects of slip, magnetic parameter and non-Newtonian fluid characteristics on the velocity and temperature fields are discussed in detail and shown graphically. Emphasis has been laid to study the effects of viscous dissipation and Joule heating on the thermal boundary layer. It is interesting to find that the non-Newtonian cross-viscous parameter has an opposite effect to that of the slip and the magnetic parameter on the velocity and the temperature fields.     

均匀自由流动的非牛顿流体中连续表面上的磁流体动力学流动和热传递

分析在平行自由流动的非牛顿黏弹性导电流体中,连续平展表面移动时的稳态流和热传递特性,该流动处于横向均匀磁场作用下.以二阶流体构建它的本构方程,得到了速度分布和温度断面图的数值结果.讨论了诸如黏弹性参数、磁场参数和Prandtl数等不同物理参数对诸种动量和热传递特性的影响,并给出相关图示.