Liquid Crystalline Complexes of Cu(II) and Pd(II) with Ferrocene-Containing Ligands

Abstract

The new liquid crystalline heteronuclear complexes Cu(II) 1a and Pd(II) 1b with a non-mesogenic ferrocene-containing β-enaminoketone L₁ of the formula C₅H₅FeC₅H₄ -C₆H₄-NH-C₂H₂-(CO)-C₆ H₄OC₁₂H₂₅, showing monotropic nematic and smectic A phases, are studied. The ortho-palladated Cl-bridged dimeric complex 3 with a non-mesogenic ferrocene-containing Schiff's base L₂ of the formula C₅H₅FeC₅H₄ -C₆H₄-N=CH-C₆H₄OC₁₀H₂₁, forming a stable smectic A phase, has been synthesized. The novel mixed-ligand heteronuclear complexes 4–7 have been obtained by treatment of the ortho-palladated complex 3 with appropriate ligands. Some of the resulting products exhibit the rather low-melting (below 100 [ddot]C) smectic A phases. Structures of the compounds are studied by elemental analysis, ¹H and ¹³C NMR, and ESR spectroscopies.

Key Words:

• metallomesogens
• ferrocene derivatives
• heteronuclear complexes
• cyclopalladated complexes