Monomeric and dimeric ortho-metallated palladium( II) -imine systems as liquid crystals

Article abstract of DOI:10.1016/0022-328X(95)05771-G

Several types of ortho-palladated complexes derived from the imines HLn = p-C_nH_{2n - 1} O-C₆H₄-CH=N-C₆H₄-OC_nH_{2n + 1}-p (n = 2, 4, 6, 8 and 10) have been prepared and their mesogenic properties studied. The types include the dinuclear complexes [Pd(μ-X)Ln]₂ with X = Cl, OAc, (R)-2-Cl-propionato or (S)-2-Br-propionato, and the mononuclear complexes [Pd(acac)Ln] and [Pd(NHacac)Ln] (NHacac = 4-amino-3-penten-2-onate). Most of the complexes (except the acetato derivatives and some others with very short alkoxy chains) show liquid-crystal behavior. Nematic, smectic A and smectic C phases are found. Most of the derivatives with chiral carboxylates display double melting behavior.