Pyridylpyrazole derivatives. A new type of mesogenic bidentate ligands inducing mesomorphism on their related PdX2 complexes

A new family of 3,5-bis(4-n-alkyloxyphenyl)-1-(pyridin-2-yl)-1H-pyrazole ligands (pypzR2) and their complexes of formula c-[PdCl2(pypzR2)] have been synthesised and their mesomorphism was investigated . The effectiveness of the asymmetric molecular design in promoting thermotropic mesophases is greater for complexes than for the related ligands, although the latter exhibit mesophases at lower temperatures. These complexes are the first example of metallomesogens containing N,N′-bidentate ligands co-ordinated to PdCl2.