TY - JOUR
T1 - High speed parallel synthesis of banana-shaped molecules and phase transition behaviour of 4-bromo-substituted derivatives
AU - Kang, Sungmin
AU - Thisayukta, Jirakorn
AU - Takezoe, Hideo
AU - Watanabe, Junji
AU - Ogino, Kumiko
AU - Doi, Takayuki
AU - Takahashi, Takashi
PY - 2004/10/1
Y1 - 2004/10/1
N2 - Novel derivative series of the well known bent-shaped P-n-O-PIMB liquid crystal mesogens, referred to as '4Br-P-n-O-PIMB', '4Cl-P-N-O-PIMB' and '5Cl-P-n-O-PIMB', having halogen atoms substituted on the phenyl ring in the central core, were synthesized by solution phase parallel synthesis based on a combinatorial approach. The mesomorphic behaviour and physical properties of all the new compounds were studied by means of optical microscopy, differential scanning calorimetry, X-ray and circular dichroism spectroscopy. We found interesting transitional behaviour for the 4Br-P-n-O-PIMB homologous series. The homologues with alkyl tails having carbon numbers of n=3-10, 12, 14 exhibit rather complicated mesomorphic behaviour, which is strongly sensitive to n. The chiral fluid smectic B2 phase with SmCAPA structure and unidentified smectic Bx phase were observed in the homologues with n = 9, 10, 12, 14 and n=3-5, respectively. Interestingly, every member exhibits frustrated and/or helical ordered phases at low temperatures, designated as X1, X2, and X3 phases, which result from a spontaneous escape from a macroscopic polarization. The mesomorphic behaviour and mesophase structures differ remarkably from those of the parent P-n-O-PIMB homologues, suggesting that substitution of the halogen atoms at the central core essentially creates a particular interaction between molecules.
AB - Novel derivative series of the well known bent-shaped P-n-O-PIMB liquid crystal mesogens, referred to as '4Br-P-n-O-PIMB', '4Cl-P-N-O-PIMB' and '5Cl-P-n-O-PIMB', having halogen atoms substituted on the phenyl ring in the central core, were synthesized by solution phase parallel synthesis based on a combinatorial approach. The mesomorphic behaviour and physical properties of all the new compounds were studied by means of optical microscopy, differential scanning calorimetry, X-ray and circular dichroism spectroscopy. We found interesting transitional behaviour for the 4Br-P-n-O-PIMB homologous series. The homologues with alkyl tails having carbon numbers of n=3-10, 12, 14 exhibit rather complicated mesomorphic behaviour, which is strongly sensitive to n. The chiral fluid smectic B2 phase with SmCAPA structure and unidentified smectic Bx phase were observed in the homologues with n = 9, 10, 12, 14 and n=3-5, respectively. Interestingly, every member exhibits frustrated and/or helical ordered phases at low temperatures, designated as X1, X2, and X3 phases, which result from a spontaneous escape from a macroscopic polarization. The mesomorphic behaviour and mesophase structures differ remarkably from those of the parent P-n-O-PIMB homologues, suggesting that substitution of the halogen atoms at the central core essentially creates a particular interaction between molecules.
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U2 - 10.1080/02678290412331298094
DO - 10.1080/02678290412331298094
M3 - Article
AN - SCOPUS:4944233096
VL - 31
SP - 1323
EP - 1336
JO - Liquid Crystals
JF - Liquid Crystals
SN - 0267-8292
IS - 10
ER -