Synthesis and liquid crystal properties of dinuclear cyclopalladated 5-alkyl-2-(4'-alkoxyphenyl)pyrimidine and 3-(4'-alkoxyphenyl)-6-alkoxypyridazine complexes

摘要

The dinuclear cyclopalladated complexes [Pd(L_1 or L_2)(μ-X)]_2 (HL_1 = 5-alkyl-2-(4'-alkoxyphenyl)pyrimidine, HL_2 = 3-(4'-alkoxyphenyl)-6-alkoxypyridazine, X = Cl~-, CH_2ClCOO~-, CH_2BrCOO~-, CH_3CHBrCOO~-, CH_2BrCH_2COO~-, CH_3COO~-) have been synthesized and characterized; their mesogenic properities were determined by DSC and polarizing microscopy. The effect of the bulk and the polarity of the bridging ligands on their mesogenic properties is discussed. The effect of the length of the alkyl chains on the mesogenic properties of these organometallic complexes has also been investigated.