Preparation and Characterization of Langmuir-Blodgett Films of Pd(II)-Imdazole Complexes

• Main Authors: Wei-Hsin Chen, 陳唯欣
• Other Authors: Y.-S. Lo
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/08588162468189004458

碩士 === 國立東華大學 === 化學系 === 93 === This thesis focuses on the preparation and characterization of molecular monolayers and multilayers of palladium(II)-imidazole complexes prepared by Langmuir-Blodgett (LB) technique. The Pd(II)-imidazole complexes used in this study, including [Pd(imCnH2n+1)2Cl2] (n = 12, 14, 16, 18) and [Pd(imCm(2-OH))2Cl2] (m = 10, 12, 14, 16, 18), are amphiphilic molecules which contain both hydrophilic and hydrophobic moieties. All of the compounds [Pd(imCnH2n+1)2Cl2] do not exhibit liquid crystalline behaviors, which may be attributed to a too small anisotropy to have sufficient core-core interaction to stabilize the mesophase. When a lateral hydroxyl group is incorporated at the 2-position of the alkyl chain in imidazole, the complexes [Pd(imCn(2-OH))2Cl2] show properties of liquid crystals. The Pd(II)-imidazole complexes form molecularly thin films at the air/water interface through self-assembly. By mechanical compression with barriers in a Langmuir trough, the molecular ordering at the air/water interface can be studied by surface pressure-area (π-A) isotherms. Molecules with longer alkyl chains produce more stable monolayer films. Incorporation of lateral hydroxyl group in the alkyl chain enhances the stability of the films via intramolecular hydrogen bonding interactions. The monolayers at the air/water interface are transferred onto solid substrate using vertical dipping LB technique. The LB films are comprised of monolayers or multilayers of Pd(II)-imidazole complexes, which are controlled by the number of deposition cycles. The surface morphology, the hydrophilicity/hydrophobicity, the surface functionalities, and the interlayer spacings of the LB films are characterized by atomic force microscope (AFM), contact-angle goniometer, reflective absorption infrared spectrometer (RAIR) and grazing-angle x-ray diffractometer (XRD), respectively.It is found that after high-temperature combustion of the LB monolayer of [Pd(imC16(2-OH))2Cl2], fairly uniform and well dispersed Pd nanopartciles are formed on the solid substrate. Further studies can be conducted to explore the applicability of this method in preparation of nanoparticles.