Successful attempts to deposit SMMs in UHV conditions\ud have been carried out with a tetranuclear iron(III) cluster [ 9 ]\ud and lanthanide bis-phthalocyaninato (LnPc 2 ) complexes. [ 10 , 11 ]\ud For the latter the seminal works of Ishikawa et al. [ 12 ] showed\ud that slow dynamics of the magnetization in these mononuclear\ud complexes is originated directly from their strong single ion\ud anisotropy. Very recently a structural and magnetic characterization\ud of a sub-monolayer deposit TbPc 2 based on synchrotronlight\ud techniques has confi rmed that this magnetic anisotropy is\ud retained on surface. [ 13 ] The absence of the observation of typical\ud slow dynamics of the magnetization has been attributed to the\ud long time-scale of the X-ray based experiments.\ud We report here a synchrotron-based investigation on neutral\ud TbPc 2 evaporated thick and thin fi lms evidencing that the thick\ud fi lm of TbPc 2 is characterized by slow relaxation of the magnetization\ud and opening of a butterfl y hysteresis cycle at temperatures\ud as high as 15 K but not observed for the thin fi lm. These\ud differences are accompanied with a drastic change in the orientation\ud of the TbPc 2 molecules in the two fi lm

Electron spin resonance (ESR), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and scanning tunneling microscopy (STM) have been used in parallel to characterize the deposition on gold surface of a series of nitronyl nitroxide radicals. These compounds have been specifically synthesized with methyl-thio linking groups suitable to interact with the gold surface to form self-assembled monolayers (SAMs), which can be considered relevant in the research for molecular-based spintronics devices, as suggested in recent papers. The degree of the expected ordering on the surface of these SAMs has been tuned by varying the chemical structure of synthesized radicals. ToF-SIMS has been used to support the evidence of the occurrence of the deposition process. STM has shown the different qualities of the obtained SAMs, with the degree of local order increasing as the degree of freedom of the molecules on the surface is decreased. Finally, ESR has confirmed that the deposition process does not affect the paramagnetic characteristics of radicals and that it affords a complete single-layered coverage of the surface. Further, the absence of angular dependence in the spectra indicates that the small regions of local ordering do not give rise to a long-range order and suggests a quite large mobility of the radical on the surface, probably due to the weak interaction with gold provided by the methyl-thio linking group.

In this paper we describe the development of a new technique based on attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy and its application to the in situ study of lubricant system behavior under tribological conditions. The lubricated tribological system consisted of a fixed steel cylinder, sliding across the surface of a germanium ATR crystal, coated with a thin iron film in the presence of the well-studied secondary zinc dialkyl dithiophosphate (ZnDTP) lubricant additive. Using this approach, changes in the additive chemistry due to adsorption, as well as reaction film growth, can be studied as a function of sliding time and temperature. The ATR FT-IR spectra reported in this work are fully consistent with the existing ZnDTP literature and show the decomposition of ZnDTP with the formation of P-O-P species following thermal testing at 150 °C, while a simple phosphate film has been detected on the iron surface following tribological testing at the same temperature.

The surface reactivity of tributyl thiophosphate on iron surfaces has been studied in situ by attenuated total reflection Fouriertransform infrared spectroscopy, X-ray photoelectron spectroscopy and temperature-programmed reaction and desorption spectroscopies. The results show that at temperatures lower than 373 K the molecule forms a physisorbed layer on the iron substrate. At 373 K a reaction takes place with the formation of an organic layer, together with iron polyphosphate and sulfate. At higher temperatures temperature-programmed desorption results suggest that the mechanism involves P-O bond scission to yield butoxy groups. This could be preceded by P=S bond scission to give tributyl phosphite, which then, in turn, undergoes P-O bond scission to produce butoxy groups. The results obtained following tribological testing are in agreement with those of thermal tests: evidence of polyphosphate and sulfate formation is found.

A tetrairon(III) single-molecule magnet is deposited using a thermal evaporation technique in high vacuum. The chemical integrity is demonstrated by time-of-flight secondary ion mass spectrometry on a film deposited on Al foil, while superconducting quantum interference device magnetometry and alternating current susceptometry of a film deposited on a kapton substrate show magnetic properties identical to the pristine powder. High-frequency electron paramagnetic resonance spectra confirm the characteristic behavior for a system with S = 5 and a large Ising-type magnetic anisotropy. All these results indicate that the molecules are not damaged during the deposition procedure keeping intact the single-molecule magnet behavior.

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We present an implementation of strategies to deposit single-molecule magnets (SMMs) using microcontact printing microCP). We describe different approaches of microCP to print stripes of a sulfur-functionalized dodecamanganese (III, IV) cluster on gold surfaces. Comparison by atomic force microscopy profile analysis of the patterned structures confirms the formation of a chemically stable single layer of SMMs. Images based on chemical contrast, obtained by time-of-flight secondary ion mass spectrometry, confirm the patterned structure.

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