RESUMO
The macrocyclization of resorcinol and odd-numbered bisdioxolanes under acidic conditions produced feet-to-feet connected trisresorcinarenes possessing three resorcinarene units linked with odd-numbered alkyl chains. The formation of trisresorcinarenes was confirmed using high-resolution mass spectrometry and NMR spectroscopy. The trisresorcinarenes were isolated as protected forms in moderate yields. The protected trisresorcinarenes exhibited D3h symmetry in conformation in solution. Crystal structure analysis revealed that the protected trisresorcinarenes possess large inner spaces surrounded by three resorcinarene units.
RESUMO
The phase diagram of a mixture consisting of hyperbranched polyester (HBPEAc-COOH) and eutectic nematic liquid crystals (E7) has been established experimentally by means of differential scanning calorimetry and polarized optical microscopy subjected to prolonged annealing. The observed phase diagram is an upper azeotrope, exhibiting the coexistence of nematic + isotropic phase in the vicinity of 90 approximately 110 degrees C above the clearing temperature of neat E7 (60 degrees C). With decreasing temperature, a focal-conic fan shaped texture develops in the composition range of 63 approximately 93 wt % of the annealed E7/HBPEAc-COOH blends, suggestive of induced smectic phase in the mixture. Wide angle X-ray diffraction (WAXD) technique revealed the existence of higher order mesophase(s).
