Columnar mesophases from half-discoid platinum cyclometalated metallomesogens

A series of liq. crystals have been synthesized and studied based upon mononuclear ortho-platinated rod-like heteroarom. and 1,3-diketonate ligands. The liq. cryst. properties of these mols. were investigated using polarized light optical microscopy, differential scanning calorimetry, single crystal x-ray diffraction, and powder x-ray diffraction. Increasing the no. of alkyl chains attached to the 1,3-diketonate units resulted in a transition from lamellar (SmA) to hexagonal columnar phases (Colh). The 2-thienylpyridine units were previously unexplored in metallomesogenic complexes and these studies extend the utility of ortho-platinated 2-phenylpyridines and 2-thienylpyridines to produce columnar liq. cryst. phases. The platinum complexes all display photoluminescence and are of interest for electrooptical applications. [on SciFinder(R)]