Reference trajectory tracking for locally designed coherent quantum controls

Local time control methods are used in the simulation of quantum control phenomena because they conveniently ensure an increase of a predefined performance index and also avoid singularities associated with tracking procedures. However, the drawback of the existing implementations is that they only take into account one-photon, direct transitions and may stop at nonoptimal values of the index. We propose in this paper a modification of the currently used algorithms that addresses this issue and explain how the convergence is improved. Furthermore, when iterations are required, we show that this approach can be inserted into a monotonically convergent algorithm.     

Enantioselective synthesis of 2-ethyl-2,3-dihydrobenzofuran carboxylic acid, direct precursor of (+)-efaroxan, from a Baylis-Hillman adduct

We describe herein a new and straightforward enantioselective approach to R-(+)-2-ethyl-2,3-dihydrofuran carboxylic acid, the direct precursor of (+)-efaroxan, an α₂ adrenoreceptor antagonist, which is indicated to be used for the treatment of neurodegenerative diseases (Alzheimer and Parkinson), migraine and type II diabetes. Our goal was accomplished using a Baylis-Hillman adduct as starting material. The dihydrobenzofuran acid was obtained in eight steps with an overall yield of 14%.     

2D LC Separation and Determination of Bradykinin in Rat Muscle Tissue Dialysate with On-Line SPE-HILIC-SPE-RP-MS

A 2D liquid chromatography (LC) system using hydrophilic interaction chromatography (HILIC) and reversed phase columns has been employed for comprehensive (LC × LC) separation of rat muscle tissue micro-dialysate. Incorporation of an on-line reverse-phase solid phase extraction (SPE) enrichment column in front of the first dimension enabled aqueous samples with high salt concentrations to be injected directly without compromising the chromatographic performance of the HILIC column. Since the SPE enrichment column allowed injection of large sample volumes (e.g. 450 μL), a capillary HILIC column (inner diameter 0.3 mm) could be employed instead of a larger column which is often used in the first dimension to load sufficient amounts of sample. The two chromatographic dimensions were connected using a column selector system with 18, 1.0 mm I.D. C₁₈ “transition” SPE columns. A PLRP C₁₈ column was used in the second dimension. The 2D LC system’s performance was evaluated with a tryptic digest mixture of three model proteins. Good trapping accuracy (HILIC→transition SPE→RP recovery >95%) and repeatability (within-and between day retention time RSDs of first and second dimension chromatography >1%) was achieved. A dialysis sample of rat muscle tissue was separated with the 2D system, revealing complexity and large differences in concentrations of the various compounds present, factors which could potentially interfere with the quantification and monitoring of two target analytes, arg-bradykinin and bradykinin. Subsequently, “Heart-cut” 2D LC-electrospray–mass spectrometry (ESI–MS) with post-column on-line standard injection was employed to monitor arg-bradykinin and bradykinin levels as a function of various muscle conditions. The method’s quantification precision was RSD = 3.4% for bradykinin.     

Polymerization Initiated by Organic Electron Donors

Polymerization reactions with organic electron donors (OED) as initiators are presented herein. The metal‐free polymerization of various activated alkene and cyclic ester monomers was performed in short reaction times, under mild conditions, with small amounts of organic reducing agents, and without the need for co‐initiators or activation by photochemical, electrochemical, or other methods. Hence, OED initiators enabled the development of an efficient, rapid, room‐temperature process that meets the technical standards expected for industrial processes, such as energy savings, cost‐effectiveness and safety. Mechanistic investigations support an electron‐transfer initiation pathway that leads to the reduction of the monomer.     

Synthesis of (1R)-1-(4-Bromophenyl)-2,2,2-trifluoroethan-1-amine Hydrochloride through Diastereoselective Trifluoromethylation of a Chiral Sulfinimine

An efficient three-step synthesis of (1R)-1-(4-bromophenyl)-2,2,2-trifluoroethan-1-amine hydrochloride ( 1 ) starting from inexpensive and readily available starting materials was developed. The sequence features a highly diastereoselective trifluoromethylation of a chiral sulfinimine using the Rupert–Prakash reagent TMSCF₃ in combination with K₃PO₄ as an initiator. The diastereomeric purity of the resulting sulfinamide was further improved by direct precipitation of the desired diastereomer from the reaction mixture upon addition of water. The chiral auxiliary was then removed under acidic conditions, resulting in the isolation of chiral benzylamine 1 as its hydrochloride salt in 71 % overall yield and excellent purity (LC/MS: >99 % a/a; e.r.=99 : 1).     

Hopf-Rinow theorem in the Sato Grassmannian

Let U₂(H) be the Banach-Lie group of unitary operators in the Hilbert space H which are Hilbert-Schmidt perturbations of the identity 1. In this paper we study the geometry of the unitary orbit

     

Renormalized charge in a two-dimensional model of colloidal suspension from hypernetted chain approach

The renormalized charge of a simple two-dimensional model of colloidal suspension was determined by solving the hypernetted chain approximation and Ornstein-Zernike equations. At the infinite dilution limit, the asymptotic behavior of the correlation functions is used to define the effective interactions between the components of the system and these effective interactions were compared to those derived from the Poisson-Boltzmann theory. The results we obtained show that, in contrast to the mean-field theory, the renormalized charge does not saturate, but exhibits a maximum value and then decays monotonically as the bare charge increases. The results also suggest that beyond the counterion layer near to the macroion surface, the ionic cloud is not a diffuse layer which can be handled by means of the linearized theory, as the two-state model claims, but a more complex structure is settled by the correlations between microions.     

A new bis(1-naphthylimino)acenaphthene compound and its Pd(II) and Zn(II) complexes: synthesis, characterization, solid-state structures and density functional theory studies on the syn and anti isomers

A new rigid bidentate ligand, bis(1-naphthylimino)acenaphthene, L1, and its Zn(II) and Pd(II) complexes [ZnCl 2( L1)], 1, and [PdCl 2( L1)], 2, were synthesized. L1 was prepared by the "template method", reacting 1-naphthyl amine and acenaphthenequinone in the presence of ZnCl 2, giving 1, which was further demetallated. Reaction of 1-naphthyl amine with acenaphthenequinone and PdCl 2 afforded dichloride bis(1-naphthyl)acenaphthenequinonediimine palladium, 2. L1, 1, and 2 were obtained as a mixture of syn and anti isomers. Compound 2 was also obtained by the reaction of PdCl 2 activated by refluxing it in acetonitrile followed by the addition of L1; by this route also a mixture of syn and anti isomers was obtained, but at a different rate. The solid-state structures of L1 and the anti isomer of compound 2 have been determined by single-crystal X-ray diffraction. All compounds have been characterized by elemental analyses; matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry; IR; UV-vis; (1)H, (13)C, and (1)H- (1)H correlation spectroscopy; (1)H- (13)C heteronuclear single quantum coherence; (1)H- (13)C heteronuclear single quantum coherence-total correlation spectroscopy; and (1)H- (1)H nuclear Overhauser effect spectrometry NMR spectroscopies when applied. Density functional theory studies showed that both conformers for [PdCl 2(BIAN)] are isoenergetic, and they can both be obtained experimentally. However, we can predict that the isomerization process is not available in a square-planar complex, but it is possible for the free ligand. The molecular geometry is very similar in both isomers, and only different orientations for naphthyl groups can be expected.