3,4-(di-n-alkyloxy)benzyl alcohol 32 and α,ω-bis[[2-(n-alkyloxy)-5-(hydroxymethyl)
phenyl]oxy]alkane 33 in different proportions and using CF 3 COOH as the cyclotetramerization catalyst (Scheme 7).
In the columnar mesophase, the backbone of the main-chain liquid-crystalline
polymer containing cyclotetraveratrylene mesogens can either connect mesogens
from adjacent columns or link two mesogens within the same column. These polymers display hexagonal columnar mesophase. All the polymers had clearing temperature in the range 102 to 145
C. The clearing temperature depends on the ratio of
32 to 33 used in reaction mixture, keeping the spacer and peripheral alkyl chain
length constant. The clearing temperature decreases on decreasing the ratio of 32 to
33 (Table 8).
RO
OR
RO
O
O
OR
OR
RO
OR
RO
O
RO
O
O
OR
RO
OR
RO
O
OR
O
O
OR RO
O
O
n
RO
RO
OH
HO
+
32
33
OH
(i)
RO
O
RO
O
O
OR
OR
RO
O
OR
( ) n
( ) n
( ) n
( ) n
34
Scheme 7 Synthesis of cyclotetraveratrylene-based main-chain polymer: (i) CF 3 COOH, CH 2 Cl 2 ,
R.T., 4.5 h (redrawn from Percec et al. 1992)
3 Liquid Crystalline Polymers Derived from Disc-Shaped Molecules
73