1402834-14-3Relevant articles and documents
Enantiotropic nematics from cross-like 1,2,4,5-tetrakis(4'-alkyl-4- ethynylbiphenyl)benzenes and their biaxiality studies
Chen, Hsiu-Hui,Lin, Hsing-An,Lai, Yin-Hui,Lin, Shu-Yu,Chiang, Chien-Hung,Hsu, Hsiu-Fu,Shih, Tzenge-Lien,Lee, Jey-Jau,Lai, Chien-Chen,Kuo, Ting-Shen
, p. 9543 - 9551 (2012/09/07)
The theoretically predicted optimum length/breadth/width ratio for maximizing shape biaxiality was investigated experimentally by the facile and successful synthesis of cross-shaped compound 3, which showed enantiomeric nematic phase behavior. This cross-like core structure could alternatively be viewed as two fused V-shaped mesogens, which have recently immerged as a new direction in biaxial nematic research, at the bending tips that can act as a new structure for biaxial investigations. Whilst the thermal analysis data of compound 3 did not meet the expected theoretical values for biaxial nematics, surface-induced biaxiality was evidenced by optical studies. Cluster-size analysis within the nematic phase of compound 3 revealed the formation of meta-cybotactic nematics, which approached the cluster sizes of cybotactic nematics. The split small-angle 2D X-ray diffraction patterns of magnetic-field-aligned samples indicated that the nematic phase was composed of small smectic C-like clusters with the tilting of molecules within the clusters. The wide-temperature-range enantiomeric nematic phase of cross-like compound 3 enabled the molecular skeleton to serve as an alternative skeleton to bent-rod mesogens, which exhibited nematic phases with the potential competition of transitions to higher-order liquid-crystalline phases and crystallization, for future biaxial investigations. Take up your cross: An enantiotropic nematic phase with a wide temperature range has been achieved by using cross-like mesogens. Biaxiality investigations by using conoscopic and 2D XRD studies imply the formation of small smectic C-like meta-cybotactic clusters in the nematic arrangement. Copyright
