Promesogen ligand

Lateral monofluorination of the p-alkoxyphenyl isocyanide system [XAu (CNC6H40C H2 +i)] (X = C1, Br, I), in ortho-(3-F) (6a) and meta-(2-F) (6b) positions relative to the alkoxy chain was also studied [18]. None of the free fluorinated ligands is a LC, but their gold complexes display mesomorphic properties. This is a typical case of a promesogenic ligand which yields a mesogen upon coordination to a metal. 

Most gold mesogens with perhaloaryl ligands as promesogen also contain isocyanide (mesogen or promesogen) ligands. Therefore, they were introduced in Section 7.2.5.3. 

Other metallomesogens containing the optically active butadienetricarbonyliron(O) moiety, incorporated into promesogenic chiral nematic ligands derived from cholesteryl, have been reported. " Both the diastereoisomers exhibited a chiral nematic phase and a monotropic smectic phase, the chiral nematic phase being monotropic for the (-l-)-isomer (Cr 193 (S 93 N 131) I), and enantiotropic for the (—(-isomer (Cr 117 (S 99) N 133 I). 

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