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Guerra, Sebastiano
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Guerra, Sebastiano
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Voici les éléments 1 - 4 sur 4
- PublicationMétadonnées seulementMacrocyclic Effects in the Mesomorphic Properties of Liquid-Crystalline Pillar[5]- and Pillar[6]arenes(2013)
; ; Nierengarten, Jean-FrancoisWhereas the reaction of 1,4-bis(2-bromoethyloxy)benzene (4) with paraformaldehyde in the presence of BF3·Et2O afforded exclusively the cyclopentameric pillar[5]arene deriv. (5), both cyclopenta- and cyclohexameric macrocycles 5 and 6 were obtained when the reaction of 4 with paraformaldehyde was performed at 45 °C in CHCl3 with FeCl3 as the catalyst. Treatment of compds. 4-6 with sodium azide provided the corresponding polyazides, to which a cyanobiphenyl building block was subsequently grafted to generate model compd. 1, pillar[5]arene 2, and pillar[6]arene 3, bearing two, ten and twelve mesomorphic subunits, resp. The liq.-cryst. and thermal properties of the compds. were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Comparison of the liq.-cryst. properties of macrocycles 2 and 3 with those of 1 revealed the strong influence of the macrocyclic pillar[n]arene core on the mesomorphic properties. Whereas only a monotropic mesophase was obsd. for 1, a broad enantiotropic mesophase was evidenced for both pillar[n]arene derivs. [on SciFinder(R)] - PublicationMétadonnées seulementBuilding liquid crystals from the 5-fold symmetrical pillar[5]arene core(2012)
; - PublicationMétadonnées seulementDesign of liquid-crystalline gold nanoparticles by click chemistryMesomorphic alkyne-based 1st- and 2nd-generation dendrons were grafted onto Au nanoparticles carrying azide groups under click reaction conditions. The nanoparticles decorated with the dendrons displayed liq.-cryst. properties and good thermal stability. [on SciFinder(R)]
- PublicationMétadonnées seulementAccordion-optimized DEPT experiments(2010)
; In this contribution, a pulse sequence is described for recording accordion-optimized DEPT experiments. The proposed ACCORDEPT experiment detects a wide range of one-bond coupling constants using accordion optimization. As a proof of concept, this strategy has been applied to a mesogen containing a large range of one-bond (1)J(CH) coupling constants associated with the various structural elements. The ACCORDEPT experiment afforded significant enhancements for the resonances with the larger (1)J(CH) couplings, similar SNR for aliphatic resonances, but reduced SNR for aliphatic resonances as compared with the standard DEPT experiment. In addition, the ACCORDEPT is straightforward to implement, does not require any supplementary calibration procedures and can be used under automated conditions without difficulty by inexperienced users. Copyright © 2010 John Wiley & Sons, Ltd.[on SciFinder (R)]