Search

Here, we applied rubbing on thiophene-basedorganic semiconductor thin films to induce a reversible mechanical amorphisation. Amorphisation is associated with fluorescence switching, which is regulated by the polymorphic nature of the film. Thermal annealing of rubbed films produces an opposite effect with respect to rubbing, inducing film crystallization. Notably, thermal crystallisation starts at a low temperature but generates the polymorph stable at a high temperature in the bulk. The mechanism of mechanical transformation is explained considering the mechanical properties of the material and demonstrated through combined X-ray diffraction, atomic force microscopy and photoluminescence at confocal microscopy. This journal is

Self-assembled monolayers (SAMs), combined with the lithography, were employed to fabricate functional surfaces. A new strategy in SAM technology, by using reiterated micro contact printing process, was proposed to produce a multi-level fluorescent TAG (multi-TAG), which consists of two overlapping micrometric patterns, made of a fluorescent oligothiophene SAM bonded with a Si/3-aminopropylthriethoxysilane substrate. The samples were characterized by fluorescence microscopy, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). In particular, the process of chemical interaction occurring during the self-assembling was investigated. The obtained results showed that the SAM process occurred with the amidic bond formation. Moreover, the grazing-angle XPS measurements indicated that the horizontal arrangement of oligothiophene molecules on the substrate surface was preferred.

We present a study on thin deposits and patterning of 1-D spin-crossover compounds FeII-(L)2H](ClO4)3 3MeOH [L = 40-(4000-pyridyl)-1,20:60100-bis- (pyrazolyl) pyridine] (1) that exhibit a reversible, thermally driven spin transition at room temperature. Micrometric rodlike crystals of 1 on silicon surfaces are achieved by drop casting and solvent annealing. We observed that the crystallinity of thin deposits and spin-transition properties critically depends on the deposition procedure. Furthermore, we proved processability and patterning using unconventional wet lithography that reduces the crystallite formation time by 1 order of magnitude. Thin deposits of 1 were characterized by atomic force microscopy, polarized optical microscopy and X-rays, and the switching properties were characterized by Raman spectroscopy.

In an attempt to change the beta-adrenergic properties of completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives, from antagonist to agonist, while still retaining the beta 2-selectivity, we described, in a previous paper, the synthesis of a series of such derivatives possessing a hydroxy or methoxy group linked to the aliphatic substituent present on the oximic carbon. However, pharmacological tests indicated that these compounds maintain the competitive antagonism on beta receptors. In this paper, the synthesis and the results of functional tests on isolated preparations are reported for a new series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives in which either the hydroxy or the methoxy group is linked to a phenyl ring present on the oximic carbon. The results obtained are then discussed, taking into account the conformational and reactivity properties of these compounds, determined by means of theoretical calculations.

In a previous paper, it had been found that completely aliphatic 3-(methylene aminoxy)propanolamine derivatives showed a good beta-blocking adrenergic activity directed prevalently towards beta 2-tracheal receptors. In an attempt to change the beta-adrenergic properties of these compounds from antagonist to agonist, while still retaining the beta 2-selectivity, a series of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives were designed in which either a hydroxylic or a methoxylic group was present on the aliphatic portion linked to the oximic carbon. The synthesis of the new compounds and their beta-adrenergic activity, evaluated by means of functional tests on isolated preparations, are described and discussed; the results obtained are then rationalised on the basis of their conformational and reactivity characteristics, determined by means of theoretical methods.