Dialkyl 2,2-bipyridine-4,4-dicarboxylate complexes of Pt-II, Cd-II and Re-I: the effects of metal centre geometry and ligand substitution on phase behaviour

Dialkyl 2,2-bipyridine-4,4-dicarboxylate derivatives are non-mesogenic ligands capable of supporting liquid crystalline phase formation when coordinated with a variety of metals. Herein is described a preliminary study on altering stable temperature ranges of thermotropic mesophases through metal centre selection and ligand modification. Characterisation of non-mesogenic CdL Cl-n(2) complexes and mesogenic ReL (n)(CO)(3)Br and PtL Cl-n(2) derivatives are presented (L (n) is the ligand with -attachment of alkyl chains, L (n) is the ligand with -attachment of chains and n is the number of carbons in the alkyl chain). Synthetic procedures and characterisation of the products by differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy and variable temperature X-ray diffraction are presented.