Single crystal X-ray analysis has been carried out for 4-hexylphenyl 4'-[(S)-2-methylbutyl]biphenyl-4-carboxylate (1), which has a phase sequence of crystal-cholesteric-isotropic, and 4-[(S)-2-methylbutyl]phenyl 4'-hexylbiphenyl-4-carboxylate (2), which has a phase sequence of crystal-S-A-cholesteric-isotropic. Crystal data:
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M(r)=428.61, C30H36O2, monoclinic, P2(1), T=298 K, a=25.697(3), b=5.7055(4), c=18.718(1)Angstrom, beta=110.124(7)degrees, V=2576.8(4)Angstrom(3), Z=4, d(x)=1.105 gcm(-3),F(000)=928.00, mu=4.49 cm(-1);
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M(r)=428.61, C30H36O2, monoclinic, P2(1), T=239 K, a=25.631(2), b=10.019(1), c=10.081(1)Angstrom, beta=94.67(1)degrees, V=25.80.1(5)Angstrom(3), Z=4, d(x)=1.103 gcm(-3), F(000)=928.00, mu=4.48 cm(-1).
Each crystal has a smectic-like layer structure, in which the molecular tilt angle is 50 degrees in 1, and 30 degrees in 2. Chiral groups are disordered in both crystals. Normal aIkyl chains are also highly disordered in 2. The features correspond to the different mesophase sequences. The layer thickness of S-A was measured for 2 by X-ray diffraction.