Résultat de la recherche
Organized Molecular Films from New Ferrocene-Containing Molecular Units
The design and synthesis of new amphiphilic ferrocene derivatives and their capability for forming Langmuir and Langmuir−Blodgett films are reported. The film formation at the air−water interface was followed by surface pressure−molecular area isotherm, surface potential−molecular area isotherm, and Brewster angle microscopy. The stability and structure of the transferred films were investigated by UV−vis spectroscopy and small angle X-ray experiments. Transfer ratios near unity were obtained. Two hydrophobic alkyl chains combined with either one or two hydrophilic functions gave stable and ordered films. One hydrophobic alkyl chain associated to one hydrophilic headgroup required the presence of an intercalant for obtaining organized molecular films. This behavior clearly illustrated the key role played by the three-dimensional structure of the ferrocene unit which tends to decrease the intermolecular interactions because of its bulkiness; this is in agreement with results reported for ferrocene-containing thermotropic liquid crystals (Deschenaux, R.; Goodby, J. W. In Ferrocenes:  Homogeneous Catalysis, Organic Synthesis, Materials Science; Togni, A., Hayashi, T. Eds.; VCH Verlagsgesellschaft:  Weinheim, 1995; pp 471−495).
An amphiphilic trinuclear cobalt cluster-containing molecular unit: synthesis, characterization and Langmuir-Blodgett films
An amphiphilic polynuclear transition-metal cluster has been prepd. and its capability for forming layers at the air-water interface and Langmuir-Blodgett films on different substrates investigated. The compd. was obtained by linking a Co3(CO)9 cluster to a hydrophobic cholesterol framework. A polar head was introduced by substituting one CO ligand by an isocyanide deriv. bearing a hydrophilic functional group. The surface pressure and surface potential vs. area isotherms and Brewster-angle microscopy indicated the formation of stable Langmuir films. Up to thirty-six transfer were performed on hydrophobized solids (mica, glass, quartz and silicon wafers). Structural characterization of the transferred films (UV and IR spectroscopy, at. force microscopy, small-angle x-ray scattering) demonstrated the formation of stable, highly organized crystals. The results represent a novel strategy towards the development of supramol. assemblies from polynuclear transition-metal compds. and organometallic surfaces. The structure of [Co3(CO)8(CCO2Me)(CNC6H4CN)] has been established by x-ray crystallog. [on SciFinder(R)]