Molecular Crystals and Liquid Crystals, Vol.534, 41-49, 2011
Dinuclear ortho-Metallated Palladium(II) Complexes with Acetato and Chloro Bridges as Liquid Crystals
In this article we present the preparation and the investigation of the liquid crystal properties of a series of dinuclear acetato- and chloro-bridged ortho-metallated Pd(II) complexes bearing six alkoxy peripheral chains in the molecule. Their structures were assigned based on elemental analysis, Infrared (IR), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, whereas the thermal behavior was investigated by polarizing optical microscopy and differential scanning calorimetry. All these complexes show mesomorphic behavior with smectic A phases being displayed. The acetato complexes exhibit a monotropic smectic A phase with transition temperatures from the isotropic state depending on the alkyl chain lengths, whereas the chloro complexes decompose on melting from the crystalline state to an SmA phase.