Core level photoemission evidence of frustrated surface molecules: a germ of disorder at the (111) surface of C60 before the order-disorder surface phase transition

Using high resolution core level photoemission, we investigated the disordering transition of the fullerene molecules at the (111) surface of C (60) films. The experimental evidence of a two-step mechanism for the rotational disordering of surface fullerene molecules is provided. The data are consistent with a recent model in which the rotational degrees of freedom of one molecule, out of the four inequivalent C (60) molecules of the low temperature (2x2) surface unit cell, melt about 100 K before the bulk phase transition.     

Nucleophilic addition of the thiocyanate ion to ferrocenyl-stabilised carbocations

The reaction of ferrocenylmethylcarbocations with the ambident thiocyanate ion produces only the isothiocyanate isomer.     

Anion recognition by functionalized single wall carbon nanotubes

Amidoferrocenyl-functionalised single wall carbon nanotubes (Fc-SWNT) are efficient exoreceptors for the redox recognition of H2PO4-.     

Thermodynamic properties of gold–water nanolayer mixtures using molecular dynamics

The physical behavior of a fluid in contact with solid layers is still not fully understood. The present work focuses on the study and understanding of thermodynamic and structural properties of gold–water nanolayer mixtures using molecular dynamics simulations. Two different systems are considered, where approximately 1,700 water molecules are confined between gold nanolayers with separations of 7.4 and 6.2 nm, respectively. Novelties of the present work are in the use of accurate force fields for modeling the inter- and intra-molecular interactions of the components, and providing comprehensive thermodynamic properties of the mixtures. The results are validated by examination of the pure fluid and pure solid properties. Results indicate that the thermodynamics of the system does not behave as an ideal mixture. The structure of the pure fluid is also analyzed and compared against the structure of the confined fluid in the mixture. Anisotropicity is observed in the fluid structure close to the surface of the nanolayer. Higher ordering and higher flux are detected in the fluid molecules close to the fluid–solid interface. Unusual thermodynamic behavior, anisotropicity, liquid layering, and higher interfacial fluid flux could be just some of the factors leading to the enhanced energy transport observed in mixtures involving at least one nanoscale component, such as nanofluids.     

Freight transportation in railway networks with automated terminals: A mathematical model and MIP heuristic approaches

In this paper we propose a planning procedure for serving freight transportation requests in a railway network with fast transfer equipment at terminals. We consider a transportation system where different customers make their requests (orders) for moving boxes, i.e., either containers or swap bodies, between different origins and destinations, with specific requirements on delivery times. The decisions to be taken concern the route (and the corresponding sequence of trains) that each box follows in the network and the assignment of boxes to train wagons, taking into account that boxes can change more than one train and that train timetables are fixed.The planning procedure includes a pre-analysis step to determine all the possible sequences of trains for serving each order, followed by the solution of a 0-1 linear programming problem to find the optimal assignment of each box to a train sequence and to a specific wagon for each train in the sequence. This latter is a generalized assignment problem which is NP-hard. Hence, in order to find good solutions in acceptable computation times, two MIP heuristic approaches are proposed and tested through an experimental analysis considering realistic problem instances.     

Graphene solutions

Thermodynamics drive the spontaneous dissolution of a graphite intercalation compound (GIC) KC(8) in NMP to form stable solutions. Reduction potential of graphene is measured at +22 mV vs. SCE. Single layer graphene flakes (ca. 1 μm(2)) have been unambiguously identified by electron diffraction.     

Ruthenium(II) complexes containing tetrazolate group: electrochemiluminescence in solution and solid state

In this work, we report the results about the solution and solid-state phosphorescence emission properties of six Ru(II) complexes containing various 5-substituted tetrazolate ligands. The photo- and electrochemiluminescence spectra of all compounds revealed a red shifted emission with respect to the Ru(bpy)(3)(2+). Significant changes to the light emission energy and to the efficiency and sensitivity to oxygen were also determined by varying the nature of the substituent ring of the tetrazolate ligand. Light-emitting solid devices with active layers containing solid films of the same complexes were prepared, and preliminary studies of their electroinduced emission properties were performed. The electrochemiluminescence (ECL) emission intensity of two of the six complexes was of the same order of magnitude as the reference Ru(bpy)(3)(2+).     

Electron transfer in pristine and functionalised single-walled carbon nanotubes

Since their very first days, electron transfer has always played a special role in carbon nanotubes' life. In view of their structural and electronic uniqueness, carbon nanotubes have been proposed either as bulk electrode materials for sensing and biosensing in advanced electrochemical devices, or as molecular-sized electrodes for very fast electrode kinetics investigations. Alternatively, electron transfer has been used to probe the electronic properties of carbon nanotubes by either direct voltammetric inspection or coupling with spectroscopic techniques, ultimately allowing, in the case of true solutions of individual uncut single-walled carbon nanotubes (SWNTs), to single-out their redox potentials as a function of diameter. For their redox properties, as emerged from these studies, SWNTs represent unique building blocks for the construction of photofunctional nanosystems to be used in efficient light energy conversion devices.     

Fullerenes: multitask components in molecular machinery

Molecular machines are molecular-scale devices that carry out predetermined tasks derived from molecular motion. This Minireview illustrates how fullerenes can be used as multitask building blocks in molecular machinery, providing new perspectives for fullerenes. Indeed, C(60) can be applied as a photo- and electroactive stopper owing to its size, as a probe for molecular motion as a result of its well-defined physicochemical properties, and to induce motion through pi-pi interactions. Such molecular motion can be employed to modulate light-driven electron-transfer events, extending the potential applications of molecular machines to the typical fields of application of fullerenes.