Nanostructured thin films obtained from Fischer aminocarbene complexes

The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO)5NH(CH2)15CH3, where R is a ferrocenyl 2(a-b) or a phenyl 4(a-b) group as a donor moiety and a Fischer carbene of chromium (0) or tungsten (0) as an acceptor group, are reported. These four push-pull systems formed Langmuir (L) monolayers at the air-water interface, which were characterized by isotherms of surface pressure versus molecular area and compression/expansion cycles (hysteresis curves); Brewster angle microscopic images were also obtained. By using the Langmuir-Blodgett (LB) method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers. LB films were characterized through ultraviolet-visible spectroscopy, atomic force microscopy and X-ray diffraction techniques. Results indicated that films obtained from 2b complex [(Ferrocenyl)(hexadecylamine)methylidene] pentacarbonyl tungsten (0) are the most stable and homogeneous; due to their properties, these materials may be incorporated into organic electronic devices

Synthesis and Characterization of Novel Dendrons Bearing Amino-Nitro-Substituted Azobenzene Units and Oligo(ethylene glycol) Spacers: Thermal, Optical Properties, Langmuir Blodgett Films and Liquid-Crystalline Behaviour

In this work, we report the synthesis and characterization of a novel series of first and second generation Fréchet type dendrons bearing amino-nitro substituted azobenzene units and tetra(ethylene glycol) spacers. These compounds were fully characterized by FTIR, 1H and 13C-NMR spectroscopies, and their molecular weights were determined by MALDI-TOF-MS. The thermal properties of the obtained dendrons were studied by TGA and DSC and their optical properties by absorption spectroscopy in solution and cast film. Molecular calculations were performed in order to determine the optimized geometries of these molecules in different environments. Besides, Langmuir and Langmuir Blodgett films were prepared with the first generation dendrons that were shown to be amphiphilic. Finally, some of the dendrons showed a liquid crystalline behaviour, which was studied by light polarized microscopy as a function of the temperature in order to determine the transition temperatures and the structure of the mesophase

Design and synthesis of benzothiadiazole-based molecular systems: self-assembly, optical and electronic properties

International audienceA set of small benzothiadiazole (BTD)-based derivatives with a D–A–D architecture were synthesized and characterized as building blocks of organic semiconducting materials by applying an experimental–theoretical approach. The four derivatives tend to self-assemble into highly ordered crystalline solids, with varying degrees of responsiveness to mechanical and thermal stimuli. The featured derivatives exhibit absorption maxima in solution and molar extinction coefficient values related to π–π* electronic transitions with minor solvatochromic responses, displaying broad fluorescence profiles with large Stokes shifts and high fluorescence quantum yields. In the solid-state, the BTD derivatives display absorption maxima in the visible range and intense fluorescence emission of the n-butoxy and fluorene derivatives. The stability of the one-electron reduced and oxidized forms of all compounds was assessed by means of cyclic voltammetry, which complemented by DFT calculations allowed the identification of one BTD derivative (BuO-BTD) as a strong candidate for use as an electron transport layer in organoelectronic devices

Nanostructured Thin Films Obtained from Fischer Aminocarbene Complexes

The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO)5NH(CH2)15CH3, where R is a ferrocenyl 2(a-b) or a phenyl 4(a-b) group as a donor moiety and a Fischer carbene of chromium (0) or tungsten (0) as an acceptor group, are reported. These four push-pull systems formed Langmuir (L) monolayers at the air-water interface, which were characterized by isotherms of surface pressure versus molecular area and compression/expansion cycles (hysteresis curves); Brewster angle microscopic images were also obtained. By using the Langmuir–Blodgett (LB) method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers. LB films were characterized through ultraviolet-visible spectroscopy, atomic force microscopy and X-ray diffraction techniques. Results indicated that films obtained from 2b complex [(Ferrocenyl)(hexadecylamine)methylidene] pentacarbonyl tungsten (0) are the most stable and homogeneous; due to their properties, these materials may be incorporated into organic electronic devices

Nanostructured thin films obtained from Fischer aminocarbene complexes

The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO)5NH(CH2)15CH3, where R is a ferrocenyl 2(a-b) or a phenyl 4(a-b) group as a donor moiety and a Fischer carbene of chromium (0) or tungsten (0) as an acceptor group, are reported. These four push-pull systems formed Langmuir (L) monolayers at the air-water interface, which were characterized by isotherms of surface pressure versus molecular area and compression/expansion cycles (hysteresis curves); Brewster angle microscopic images were also obtained. By using the Langmuir-Blodgett (LB) method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers. LB films were characterized through ultraviolet-visible spectroscopy, atomic force microscopy and X-ray diffraction techniques. Results indicated that films obtained from 2b complex [(Ferrocenyl)(hexadecylamine)methylidene] pentacarbonyl tungsten (0) are the most stable and homogeneous; due to their properties, these materials may be incorporated into organic electronic devices