Search results for "algebra"
showing 10 items of 4129 documents
Cover Feature: Green‐Light Activation of Push–Pull Ruthenium(II) Complexes (Chem. Eur. J. 30/2020)
2020
Cross-Linked Polyamine from Imidazolium-Based Materials: A Simple Route to Useful Catalytic Materials
2018
Alternating Ferro/Antiferromagnetic Copper(II) Chain Containing an Unprecedented Triple Formato/Hydroxido/Sulfato Bridge.
2016
The first example of a triple formato/hydroxido/sulfato (FHS) bridge for any metal is reported in compound [Cu2(bpym)(OH)(HCO2)(SO4)(H2O)2]·3H2O (1). Its structure shows the presence of alternating triple FHS bridges and 2,2'-bipyrimidine (bpym) ones. Although in the initial synthesis the sulfate anions were introduced accidentally, here we report the rational synthesis and the magnetic properties of this compound. The magnetic properties show that 1 is an alternating ferro/antiferromagnetic (F/AF) chain compound with predominant antiferromagnetic interactions and were fit to an alternating F/AF S = (1)/2 chain with g = 2.103, JAF = -139 cm(-1), and JF = 116 cm(-1) (α = JF/|JAF| = 0.83). Th…
Spatial Demixing of Ring and Chain Polymers in Pressure-Driven Flow
2019
We investigate mixtures of ring and linear polymers in solution at various number ratios, ranging from pure chains to pure rings, and at densities around the overlap concentration. In bulk and at r...
Reaction of an open-chain analogue of Reissert compound hydrofluoroborate salt with ethyl acrylate. A reinvestigation
1998
Abstract The reaction of an open-chain analogue of Reissert compound hydrofluoroborate salt with ethyl acrylate does not give a [4+2] cycloadduct as previously described, but a [3+2] cycloadduct which evolves to a 2-pyridone 15.
ChemInform Abstract: A Novel Synthesis of Chain-Extended Amino Sugar Derivatives Through Aza-Cope Rearrangement of N-Galactosyl-N-homoallylamines.
2010
Abstract Chain-extended amino sugars are synthesized via stereocontrolled Lewis acid-catalyzed aza-Cope rearrangement of N-glycosyl homoallylamines in high yield and stereoselectivity.
A novel synthesis of chain-extended amino sugar derivatives through aza-Cope rearrangement of N-galactosyl-N-homoallylamines
1998
Abstract Chain-extended amino sugars are synthesized via stereocontrolled Lewis acid-catalyzed aza-Cope rearrangement of N-glycosyl homoallylamines in high yield and stereoselectivity.
Amphiphilic Polyethers of Controlled Chain Architecture
2003
The amphiphilic polymers, polymers which contain in their macromolecules both hydrophilic and hydrophobic units1, are the base for valuable materials due to their diversified interaction with liquids. So they may act as emulsifiers, compatibilizers, “smart” materials (responding to external stimuli)2 and many others. In order to control their properties, the hydrophilic — hydrophobic balance in the macromolecules has to be controlled. This balance depends not only upon the constitution of the chain repeating units, but also upon the art of their distribution in the chains (copolymers of controlled unit sequences), the chain topology, the size of the chains and many others. So a careful engi…
Monte Carlo simulation of the glass transition in polymeric systems: Recent developments
1995
Abstract The bond fluctuation model on square and s.c. lattices is used as a coarse-grained model for flexible polymers in dense melts. Using an energy that favours long bonds, a conflict is created between the tendency of the bonds to stretch at low temperatures and packing constraints. This simple concept of ‘geometric frustration’ leads to glass transition. Both static and dynamic properties of this model are investigated by Monte Carlo simulations, paying attention to effects found by varying the cooling rate and the chain length N of the polymers. In two and three spatial dimensions an effective (cooling-rate dependent) glass transition temperature T g can be defined, where the system …