THE RELATIONSHIP BETWEEN MOLECULAR-STRUCTURE AND MESOMORPHIC PROPERTIES OF 2,2'-DIFLUOROTERPHENYLS AND 3,2'-DIFLUOROTERPHENYLS SYNTHESIZED BY PALLADIUM-CATALYZED CROSS-COUPLINGS
M. Hird et al., THE RELATIONSHIP BETWEEN MOLECULAR-STRUCTURE AND MESOMORPHIC PROPERTIES OF 2,2'-DIFLUOROTERPHENYLS AND 3,2'-DIFLUOROTERPHENYLS SYNTHESIZED BY PALLADIUM-CATALYZED CROSS-COUPLINGS, Liquid crystals, 18(1), 1995, pp. 1-11
Several homologues of two structurally different types of mesogenic di
fluoroterphenyls have been prepared. One set of compounds contains two
inner-core fluoro-substituents and the other set possesses both an in
ner-core and an outer-core fluoro-substituent. The use of various type
s of palladium-catalysed cross-coupling reactions was invaluable in th
e synthesis (for example, selective couplings, and couplings to triflu
oromethanesulphonate derivatives). Additionally, a novel selective lit
hiation is reported. The mesogenic materials are all low melting and t
he types of mesophase generated are considerably structure dependent.
However, most of the materials support the tilted S(C) phase which is
required of ferroelectric host materials. The mesomorphic behaviour of
these novel materials is discussed in terms of the molecular structur
e and the structure/property relationships are compared with those for
difluoroterphenyls with different arrangements of lateral fluoro-subs
titution.