Biaxially oriented polyethylene terephthalate (PET) films were exposed to oxygen-implicated plasma. They were pressed at 100℃ with their exposed surfaces faced, then bonded tightly without using glue. X-ray photoelectron spectroscopy showed increase in C=O group at the exposed surface, and gas chemical modification method showed increases in-OH and-COOH groups. They might indicate that a mechanism of the two-sheets bonding is related to hydrogen bond or condensation reactions concerning these functional groups.
In this article it is reviewed on enigmatic electrical and magnetic properties of La(Ba)Mn0 3 thin films, useful for tunable microwave filters. As-grown films have well separated insulating to metallic (Tp) and paramagnetic to ferromagnetic (Tc) transition temperatures, which can be understood from the phase separation model. The film shows negative magnetoresistance (MR) caused by normal double exchange coupling effect, and positive MR which is interpreted by a magnetostriction effect. The phase separation is caused by crystal strain in the film. By annealing these two temperatures, Tp and Tc, become more separated, implying a size reduction of ferromagnetic grains. The phase separation scenario can be confirmed by ferromagnetic resonance (FMR) showing doublet signals. The FMR indicates anisotropic phase transition which supports the magnetostriction model. Moreover, the narrow FMR signals suggest high spin ordering and good crystallinity.
et al.. Enantioselective deprotometalation of N,N-dialkyl ferrocenecarboxamides using metal amides.1 TOC Our attempts to deprotometalate N,N-dialkyl ferrocenecarboxamides enantioselectively by using chiral lithium or lithium-zinc dialkylamides are reported.
Abstract:N,N-Diisopropylferrocenecarboxamide can be enantioselectively deprotometalated by combining butyllithium with (-)-sparteine in diethyl ether at low temperature. It is of interest to identify conditions that could allow substrates bearing more reactive functional groups (such as esters and ketones) to be similarly converted. We here report our efforts to use different chiral lithium-zinc bases, made from a simple chiral lithium amide, (R,R)-or (S,S)-lithium bis (1-phenylethyl)amide (PEALi), for the enantioselective deprotonation of N,N-diisopropylferrocenecarboxamide. First, different zinc-based in situ traps were employed to intercept the formed ferrocenyllithium; optimization using enantiopure lithium bis[1-(S)-phenylethyl]amide ((S)-PEALi) led to the 2-iodo derivative in 96% yield and 69% ee in favor of the RP enantiomer. The method was extended to N,N-dimethylferrocenecarboxamide, morpholinoferrocenecarboxamide and N,N-diethylferrocenecarboxamide; for the latter, similar yield and enantioselectivity were recorded. DFT calculations on a model reaction showed very small differences between the activation energies leading to (RP)-and (SP)-2-lithioferrocenecarboxamides. Next, the behavior of various mixed amino-alkyl lithium zincates of the types R2[(S)-PEA]ZnLi and R2[(S)-PEA]2ZnLi2 (R = alkyl) was studied, notably by varying the reaction temperature and time, and the amount of base. The best results were obtained with Me2[(S)-PEA]2ZnLi2, affording the 2-iodo derivative in 97% yield and 86% ee in favor of the SP enantiomer.
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