Synthesis of Liquid Crystalline Phosphazenes Containing Chiral Mesogens

Phosphazene cyclic trimers and high polymers containing biphenyl side groups with (S)-2-methyl-1-butoxy as a terminal unit were synthesized. The chiral biphenyl units [4,4'-C sub(6) H sub(4)C sub(6)H sub(4)OCH sub(2)-CH(CH sub(3))CH sub(2)CH sub(3)] were linked to the skeletal phosphorus atoms...

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Bibliographic Details
Published in:Macromolecules 1995-06, Vol.28 (13), p.4351-4360
Main Authors: Allcock, Harry R, Klingenberg, Eric H
Format: Article
Language:English
Subjects:
Applied sciences
Atoms
Chemical modifications
Differential scanning calorimetry
Exact sciences and technology
Inorganic and organomineral polymers
Macromolecules
Molecules
Morphology
Optical microscopy
Phosphorus compounds
Physicochemistry of polymers
Synthesis (chemical)
Thermodynamics
X ray crystallography
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Summary:Phosphazene cyclic trimers and high polymers containing biphenyl side groups with (S)-2-methyl-1-butoxy as a terminal unit were synthesized. The chiral biphenyl units [4,4'-C sub(6) H sub(4)C sub(6)H sub(4)OCH sub(2)-CH(CH sub(3))CH sub(2)CH sub(3)] were linked to the skeletal phosphorus atoms of the small-molecule phosphazene cyclic trimers and high polymers through -O(CH sub(2)Ch sub(2)O) sub(m) - spacer linkages, where m identical with 2 or 3. Of the cyclic trimers synthesized, with the formula N sub(3)P sub(3)[O(CH sub(2) CH sub(2)O) sub(m)C sub(6)H sub(6)C sub(6)H sub(4)OCH sub(2)CH(CH sub(3)) CH sub(2)CH sub(3)] sub(6) where m identical with 2 (4) or 3 (5), only 5 was liquid crystalline, as determined by differential scanning calorimetry (DSC). Single-substituent high-polymeric poly(organophosphazenes) were synthesizedthat contained the chiral biphenyl unit linked to the backbone through spacer units m identical with 2 (6) and 3 (8). Cosubstituent polymers were also synthesized which contained both the chiral biphenyl derivative linked to the backbone through varying spacer lengths and with nonmesogenic cosubstituents, OCH sub(2)CH sub(2)OCH sub(2)CH sub(2)OCH sub(3) and OCH sub(2)CF sub(3). The liquid crystalline behavior of these polymers was studied with respect to spacer length and nonmesogenic cosubstituents. All the polymers synthesized showed enantiotropic liquid crystallinity. Morphologies and thermal behavior of these compounds were investigated with the use of DSC, X-ray diffraction, and optical hot stage microscopy.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma00117a001