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The spreading monolayers at the air-water surface of the mesogenic, discotic copper(II) derivatives of 2,3,7,8,12,13,17,18-octakis(alkylthio)porphyrin (CuTAP) have been characterized with the aim of finding the best experimental conditions for fabricating Langmuir-Blodgett (LB) films with columnar aggregates having significant mono- and/or bidimensional properties. The spreading isotherms of pure metal compounds were interpreted in terms of inhomogeneous, rigid surface films, not suitable for LB film deposition. A better transfer was reached with mixtures (e.g. 1 20 molar ratio) of Cu-TAP with the film forming stearic acid, thus obtaining stable and reproducible LB films with more than 300 layers. The film maintained a disordered state of columnar aggregates as proved by electron spin resonance and UV-visible spectroscopy.

We studied the properties of the monolayers and deposition behaviour of a new member of the group of bis-porphyrin complexes of rare earth metals, namely the newly fabricated lutetium(III) bis-2,3,7,8,12,13,17,18-octakis(butylthio) tetraazaporphyrinato, as a pure compound and in mixture with cadmium stearate, in the light of their magnetic, semiconducting and gas sensing properties. In both cases the molecules assumed a tilted edge-on orientation at the liquid-air interface, with the molecular rings perpendicular to the water surface, as deduced from π−A isotherms. Multilayer Langmuir-Blodgett (LB) films were successfully built up only when the bis-porphyrin molecules were mixed with cadmium stearate. Electronic absorption spectra using plane-polarized light indicated isotropy in the plane of the film, i.e. the axes of the molecules were randomly oriented in this plane. The peak width at half-height for the Q band increased on passing from the chloroform solution to the LB films of pure and mixed compounds, indicating different degrees of molecular packing. A single electron spin resonance line was given by the chloroform solution of the molecule and it was also maintained in the mixed LB film.

The properties of monolayers and multilayers of nickel(II) compounds with the dinaphtho derivative of the macrocycle ligand dinaphtho{ b,i }5,7,12,14-tetramethyltetraaza[14]annulene with one and two hexadecanoyl chains on the water surface and onto a solid support have been studied from a thermodynamic and spectroscopic point of view and the results were compared with those from the dibenzo analogues. The molecular plane showed a tilted edge-on orientation at the air-water interface. The spreading monolayers were stable with time and their stability was almost independent of the compound used. The presence of hysteresis in the compression-expansion-compression cycles indicated an incomplete reversibility. Films prepared with the monohexadecanoyl macrocycle metal derivatives were regular and homogeneous whereas the occurrence of two alkyl chains on the ring resulted in a monolayer too viscous to be transferred. The effect of the film iodination was investigated through UV-visible and electron spin resonance spectroscopies.

The interactions between monolayers of behenic acid or dihexadecylphosphoric acid (DHP) with mono- and multivalent metal ions in the aqueous subphase were studied tp find the best conditions for the layer transferance on solid supports as LB films. The thermodynamic parameters, the ellipsometric and spectroscopic data allowed us to assess that condensed phases of the monolayer and appreciable surface association between metal ions and ionized amphiphilic were the main requirements to be fulfilled.

The spreading monolayers at the air-water interface of ceramide (CER) and dioleoylphosphatidylcholine (DOPC), as pure compounds and in mixtures, in the 15–30°C temperature range, were studied using two different subphases, containing NaCl (0.1 M) and a phosphate buffer (pH 7), respectively. The bidimensional phases of the pure compounds, their miscibility and the excess free energy of mixing, ΔGmix, were determined. The results showed a surface compatibility of the two components over the whole range of temperatures, either using the Na+ ion-containing subphase or the buffered subphase.

In this paper we report information on the spreading isotherms and the electron spin resonance (ESR) spectra of mono- and multilayer films built up with long hydrocarbon chain nitroxides (namely doxyl stearic acid and hexadecanoyl- piperidine-oxyl radicals). These ultrathin molecular assemblies were prepared from (i) single components, (ii) nitroxide binary mixtures, and (iii) a diluted solution of the paramagnetic components in a diamagnetic (stearic acid) host. The spreading isotherms allowed us to establish that the presence of a five- or six-membered ring in the hydrocarbon chain rendered the film more expanded, and this effect depended on the substituent position in the chain. The ESR spectra of undiluted nitroxides were characterized by strong spin-spin (dipole-dipole and Heisenberg spin exchange) magnetic interactions whose extent also depended on the nitroxide type and mixture. The calculation of the parameters of motion governing the ESR lineshape allowed accurate evaluation both of the degree of order and of the chain flexibility, particularly for diamagnetically diluted systems.