Synthesis, characterization of Cu(II) and Ni(II) liquid crystal complexes of an unsymmetrical beta-diketone containing a terminal double bond

The unsymmetrical beta-diketone-type ligand [H(DK-11-12)] containing a term inal double bond derived from 4-dodecyloxyacetophenone (A) and methyl 4-und ecenyloxybenzoate (B) and its complexes [M(DK-11-12)(2)] (M = Cu, Ni) were synthesized and characterized by elemental analyses, molar conductivity, IR , electronic spectra, H-1 NMR and magnetic susceptibility measurements. The ligand functions as an uninegative bidentate and bonds through the two oxy gen atoms of the cis-enol moiety. The two complexes are nonelectrolytes and have square-planar geometry. The mesogenic behaviors of the beta-diketone- type ligand and the complexes were determined via a combination of observat ion on a hot-stage polarized microscope and DSC measurements. The ligand ha s no liquid crystallinity. The complexes are liquid crystals whose mesogeni c textures are a type of broken-fan. The transition processes of the comple xes were tentatively proposed to be K-->S-->I.