The Reaction of α,α-Dichlorobenzyltrimethylsilane with Aldehydes and Ketones

The reaction of α,α-dichlorobenzyltrimethylsilane with carbonyl compounds in the presence of fluoride ion fails to give reasonable yields of the α,α-dichlorobenzyl adducts except when carried out in the presence of zinc iodide and in HMPA as solvent. Under these conditions moderate yields of the adducts can be obtained with cyclohexanone, cyclohexenone, benzaldhyde and trans cinnamaldehyde. These reactions were compared with those of α,α-dichlorobenzyllithium.     

Trichloromethyl Anion Chemistry from Trimethylsilyl Trichloroacetate

The reaction of trimethylsilyl trichloroacetate with aldehydes and Retones in the presence of fluoride ion gives the trichloromethyl adducts. With potassium fluoride the reaction with cyclohexenone and crotonaldehyde results in clear 1,2 addition.     

Synthesis of a diversifiable cis-dehydrodecalin scaffold based on meiogynin A

A highly endo selective Diels-Alder reaction provides efficient access to the substituted cis-dehydrodecalin core structure of meiogynin A. Elaboration into the fully functionalized scaffold was achieved in three steps from cycloadduct 20a. This strategy is amenable to the synthesis of diversely substituted meiogynin analogs for the discovery of novel inhibitors of Bcl-xL and related anti-apoptotic proteins.     

The transverse electron scattering response function of 3He

Results on the transverse response function R _T (q,ω) of ³He obtained within the Lorentz integral transform [LIT] [1] method are presented. The response is calculated using the BonnRA nucleon-nucleon potential [2], the Tucson-Melbourne [3] three-body force, and the Coulomb potential for various momentum transfers. The results are compared with available data.     

Evidence for an internal field in CdSe/CdS nanorods by time resolved and single rod experiments

In this contribution we report on an optical nonlinearity featuring colloidal seeded grown CdSe/CdS nanorods (NRs). It consists of a photoluminescence (PL) blueshift of single rod spectra with increasing laser power and a transient, power-dependent redshift of the spectra studied by time resolved PL measurement, strictly related to the multicarrier scattering occurring at high excitation density. We attribute this nonlinearity to a photo-induced screening of an internal field, originating from the piezoelectric polarization induced at the core/shell interface.     

Synthesis and characterization of poly(3-alkylthiophenes) with NLO chromophoric groups in side chains

Polythiophene copolymers containing alkyl side chains of different length and partially functionalized with chromophoric groups have been synthesized by FeCl₃ oxidative coupling of 3-alkylthiophenes and functionalized 3-alkylthiophenes. Composition, molecular weigth and configuration of the soluble fraction of the copolymers have been investigated and some structure-property correlations have been evidenced.     

Diffusion of Organic Vapors in Materials for Gas Sensing Application

Mass-variation measurements were carried out on carbon black (CB)-poly(vinyl chloride) (PVC) composite film with 40% by weight of di(2-ethylhexyl)-phthalate (DOP), cast on resonant piezo-layer (RPL) elements of lead zirconat titanate (PZT). Even if anomalous diffusion is predicted by fitting the data with M_t/M_∞=kt^α, the fractional uptake M_t/M_∞ is linear with the square root of the time up to M_t/M_∞=0.6, suggesting Fickian behavour. The anomalous values of α are probably due to experimental time lag. A dependence of the diffusion on the morphology of the material and the penetrant shape and flexibility has been found.