Beilstein J. Org. Chem.2012,8, 472–485, doi:10.3762/bjoc.8.54
studied by optical polarizing microscopy (PM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). All dimesogens exhibit broad ranges of cybotacticnematicphases (NcybA and NcybC), in some cases accompanied by additional mesophases (CybA or SmC) at lower temperature. The combination of
the 3,5-diphenyl-1,2,4-oxadiazole unit with one cyanobiphenyl core leads to the removal of tilted smectic and cybotacticnematicphases (SmC, NcybC), which are replaced by the nontilted CybA phases and nematic phases composed of SmA-type clusters (NcybA). The orthogonal cybotacticnematicphases of
bent-core mesogens are of special interest for achieving biaxial nematic phases of the orthorhombic type. The orthogonal (NcybA) and skewed (NcybC) cybotacticnematicphases were distinguished by XRD and optical observations.
Keywords: bent-core mesogens; cybotacticnematicphases; dimesogen; liquid
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Graphical Abstract
Scheme 1:
Structures of the investigated ABA-heterotrimesogens CB-Ox-CB/n and heterodimesogens CB-Ox/n, Thia-...