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The fluorophobic effect of the semi-fluorinated chain of discotic molecules efficiently improves the stability of columnar mesophase.Low symmetric discogens exhibit decreased melting points and wide mesophase ranges.A series of triphenylene derivatives 1,C18H6(OCnH2n+1)4(OMe)(O2CC2H4C6F13),and their hydrocarbon analogues 2,C18H6(OCnH2n+1)4(OMe)(O2CC8H17),n = 4―8,were synthesized for the investigation of the influence of semi-fluorinated peripheral chain and molecular symmetry on mesomorphism.The structures were characterized with 1H NMR and MS.The mesomorphism was studied with differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).The results showed that all triphenylene derivatives exhibited enantiotropic columnar mesophase.The semifluorinated triphenylenes 1a―1e displayed higher melting points and clearing points than their hydrocarbon analogies 2a―2e.Most of them were in columnar mesophase at room temperature.
The fluorophobic effect of the semi-fluorinated chain of discotic molecule efficiently improves the stability of columnar mesophase. Low symetric discogens exhibit decreased melting points and wide mesophase range. A series of triphenylene derivatives 1, C18H6 (OCnH2n + 1) 4 (OMe) ( (OCnH2n + 1) 4 (OMe) (O2CC8H17), n = 4-8, were synthesized for the investigation of the influence of semi-fluorinated peripheral chain and molecular symmetry on mesomorphism.The O2CC2H4C6F13, and their hydrocarbon analogues 2, C18H6结构 所 characterized with 1H NMR and MS.The mesomorphism was studied with differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The results showed that all triphenylene-derivatives exhibited enantiotropic columnar mesophase. semicluorinated triphenylenes 1a-1e displayed higher melting points and clearing points than their hydrocarbon analogies 2a-2e. Mortost of them were in columnar mesophase at room temperature.