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The use o
f blends in which a mesogen induces mesomorphism into a non-mesogenic compound hasma
de possible the sel
f-organization o
f phthalocyanine-[60]
fullerene (Pc-C
60) dyads into liquid crystals.Pc-C
60 dyads
1,
2, or
3, in which two photoactive units are brought together by a phenylenevinylenespacer, have been synthesized through a Heck reaction that links 4-vinylbenzal
dehy
de to a monoiodophthalocyanine precursor,
followed by standard cycloaddition o
f azomethine yli
des-generated
from the
formylPc
derivative and
N-methylglycine-to one o
f the double bonds o
f C
60. The mesomorphic andthermal properties o
f di
fferent mixtures
formed by the liquid-crystalline phthalocyanine
4 and dyads
1,
2, or
3 were examined using polarizing optical microscopy (POM), di
fferential scanning calorimetry(DSC), and X-ray di
ffraction (XRD). DSC diagrams o
f the blends show clear transitions
from the crystallinestate to a mesophase, and the measured structural parameters obtained
from the pow
der di
ffractionexperiments are consistent with a discotic hexagonal columnar (Col
h) structure. Consi
dering that segregationin domains o
f separated molecules o
f Pc-C
60 dyad and phthalocyanine
4 would preclu
de mesomorphismdue to the mismatch in the column diameter and to the lack o
f mesogenic character o
f the pure dyads,a predominance o
f alternating stacking is proposed. Additionally, the observed
decrease in the calculated
density o
f the blend mesophases relative to the mesophase o
f pure compound
4 is important evi
dence inthis direction.