Molecular orbital treatment of phenylfurans and bifurans

The molecule-in-molecule method of computation has been applied in a SCF study of the electronic absorption spectra of 2- and 3-phenylfurans and 2,2′- and 3,3′-bifurans. The computed values for the transition energies and band intensities differ for the different isomers and help one to assign the preferred conformer of the studied molecules. Computations were performed on planar as well as nonplanar conformers. The calculated parameters as well as the interaction energy suggest all-planar configuration for the studied molecules. A model potential for the sigma framework for the ortho-hydrogens is considered. The calculated steric repulsion energy is negligible compared to the π delocalization. The height of the rotational barrier was larger for 2-phenylfuran than for 3-phenylfuran, and larger for 2,2′-bifuran than for 3,3′-bifuran. This result is in accord with predictions based on the extent of “π” conjugation in these molecules.     

Regioselective Diastereomeric Michael Adducts as Building Blocks in Heterocyclic Synthesis

The reaction of 4‐(4‐acetylamino/bromophenyl)‐4‐oxobut‐2‐enoic acids with carbon nucleophiles afforded Michael adducts depending on the type of nucleophilic reagents and medium (acidic or basic). The adducts 2 and 3 were used as key starting materials to synthesize some heterocyclic compounds, which include pyridazinone, furanone, 1,2‐oxazin‐5‐one, 1.2‐diazapine, pyrane, and hydroxyl pyridine derivatives. The Steric factor plays an important role in regioselectivity. The structure of newly synthesized compounds was elucidated by elemental analysis and spectroscopic data.     

The Role of Transport Phenomena and Modeling in the Development of Thermal Plasma Technology

A brief overview is presented of the principal areas where thermal plasmas had a significant technological impact over the past century. This is followed by an analysis of the specific role played by modelling and studies of transport phenomena under plasma conditions for three specific examples. The first dealing with the development of inductively coupled plasma sources. The following two examples deals with process development for the in-flight melting and spheroidization of powders, and the synthesis of nano-powders. Emphasis is placed on the critical role of plasma–particle interactions under dense loading conditions. A proposal is made for a relatively simple thermodynamic model which can be used for the estimation of the theoretical limits for the processing rates possible with different powders in each of these two cases. The model takes into account radiative energy losses from the surface of the particles and from the formed vapor cloud in the plasma, as well as the residual energy in the gases at the exit of the plasma reactor which are not accessible for process needs.     

Synthesis and anticancer activity of novel quinazolinone and benzamide derivatives

Research on Chemical Intermediates - In trying to develop new anticancer agents, a series of quinazolinone and benzamide derivatives were synthesized via reaction of...     

Thienopyrazine‐Based Low‐Bandgap Poly(heteroaryleneethynylene)s for Photovoltaic Devices

Summary: Low‐bandgap π‐conjugated polymers that consist of alkyl thiophene/alkoxy phenylene and 2,3‐diphenylthieno[3,4‐b]pyrazine units have been prepared in high yields by a Sonogashira polycondensation. The copolymers are characterized by NMR, IR, UV, GPC, and elemental analysis. Thin films of the polymers P1 , P2 , and P3 exhibit an optical bandgap of ≈1.57–1.60 eV. Under simulated AM 1.5 conditions P2/PCBM devices on polyester foil provide a short circuit current of I_SC = 10.72 mA · cm⁻², an open circuit voltage of V_oc = 0.67 V, and a power conversion efficiency of 2.37%.

Schematic of the photovoltaic device made from the polymers synthesized here.     

Particles with Magnetic Patches: Synthesis,Morphology Control,and Assembly

The concept of patchy particles is revolutionizing the research field of colloidal assembly, by the design of particles whose surface is purposely patterned to promote attractive interactions with their neighbors in limited number, and in privileged and programmed directions. The idea of magnetic patches makes it possible to imagine assemblies not only spontaneous by simple magnetic coupling but also triggered and canceled at will due to external magnetic fields. This review shows that studies published until now mainly deal with particles with a single magnetic patch, often called Janus particles. The very diverse synthetic routes have been brought together into four main strategies, covering the size range from 100 nm to 100 µm. Their assembly capacity is described both from experimental and simulation viewpoints. The orientation of the magnetic moment of the patch and its decentering extent with respect to the particle are the key parameters for controlling the morphology of clusters, loops, staggered chains, double chains, helices, microtubes, etc. The review offers some perspectives to generalize these studies to multipatch particles, examples of which are still too rare, and to make assemblies sustainable, especially after the removal of the structuring magnetic fields.     

Leray–Schauder alternatives for weakly sequentially continuous mappings and application to transport equation

Motivated by the study of a general radiative transfer problem, we state some new variants of Leray–Schauder type fixed point theorems for weakly sequentially continuous operators. Further, we apply our results to establish some new existence and locality principles for a source problem in L₁‐setting with generally boundary conditions. Copyright © 2009 John Wiley & Sons, Ltd.