Chemistry Reference
In-Depth Information
(a)
CH
2
CH
2
O
-
ClOC
(CH
2
)
n
COCl
SnBu
2
O(CH
2
)
4
O
CO
(CH
2
)
n
CO
- BuSnCl
2
CH
2
CH
2
O
(b)
(c)
CH
2
CH
2
S
CH
2
S
SnBu
2
CH
2
SnBu
2
CH
2
CH
2
S
CH
2
S
ClOC
(CH
2
)
m
CO
C
l
-
- 2 ClSiMe
2
O
CO
(CH
2
)
m
CO
O
OSiMe
3
Me
3
SiO
ClOC
(CH
2
)
m
CO
C
l
-
CO
OSiMe
3
Me
3
SiO
O
- 2 ClSiMe
3
(d)
CO
(CH
2
)
m
CO
O
O
CO
O
Formula 7.2
polycondensations of the same monomers in isotropic solutions. The predomi-
nance of the even-membered cycles indicates that the linear precursors existed in a
folded conformation with a parallel alignment of the mesogenic moieties.
Further studies were devoted to syntheses of polyamides [
60
,
61
] via KC
polycondensations. The monomer combinations were selected so that polyamides
having a moderate or good solubility in the reaction media were obtained, so that
early precipitation of linear chains from the reaction mixture was prevented (e.g.,
(a) in Formula
7.3
). From the best experiments spectra exclusively displaying
mass peaks of cyclic polyamides up to 13 kDa were obtained. Similar results were
found for soluble polyimides derived from the dianhydrides (b) and (c) (in For-
mula
7.3
) and various aromatic diamines [
62
,
63
].
