Centered rectangular mesophase

Note 3 The SmA mesophase is also known as a centered rectangular mesophase or anti-mesophase. The dimensional space group is cmm in the International System. 

Complexation of 100 with carbonyl complexes of chromium, molybdenum, and tungsten yielded liquid crystalline complexes lOla-c [114] (Scheme 50). All derivatives 101 melted at similar temperatures into the columnar rectangular mesophase (deduced from WAXS and SAXS measurements). However, the clearing points were strongly dependent on the metal center and increased with increasing atom number. Upon complexation, the aza crown macrocycle loses its flexibility, with the metal carbonyl fragment located above the crown leading to a cone-shaped... 

The SmA (monomolecular organization) nature of the mesophase displayed by 32 is due to the head-to-tail orientation of the molecules within the mesophase. The columnar phase obtained for 33 was found to have a centered rectangular symmetry. The discrepancy between the molecular volume of the flexible tail and that of the rigid rod is responsible for the formation of the columnar phase. 

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