Strengthening the Connection between Science,Society and Environment to Develop Future French and European Bioeconomies: Cutting-Edge Research of VAALBIO Team at UCCS

The development of the future French and European bioeconomies will involve developing new green chemical processes in which catalytic transformations are key. The VAALBIO team (valorization of alkanes and biomass) of the UCCS laboratory (Unité de Catalyse et Chimie du Solide) are working on various catalytic processes, either developing new catalysts and/or designing the whole catalytic processes. Our research is focused on both the fundamental and applied aspects of the processes. Through this review paper, we demonstrate the main topics developed by our team focusing mostly on oxygen- and hydrogen-related processes as well as on green hydrogen production and hybrid catalysis. The social impacts of the bioeconomy are also discussed applying the concept of the institutional compass.     

Electrical conductivity in HMTSF-TNAP under pressure

The resistivity of the organic conductor HMTSF-TNAP has been measured at pressures up to 25 kbar and at temperatures down to 1.2 K. Under pressure the increase in the stacking axis resistivity of HMTSF-TNAP (Δ^2,2 -Bi(4,5-trimethylene-1,3-diselenole)-11,11′,12,12′-tetracyano-2m6- naphtoquinodimethane) below 47 K is reduced, although the transition temperature T_p falls at only 0.7 K kbar^?1. This weak pressure dependence compared to that of HMTSF-TCNQ correlates with the larger resistivity anisotropy in the TNAP salt.     

Precision and control in polymer synthesis why it's important and some recent examples of how to do it

This paper discusses some of the reasons why precision and control in polymer synthesis is of importance. By way of illustration it describes in outline recent results from the authors' laboratories in three areas. Namely; the controlled syntheses of poly(arylene vinylene)s and the influence of cis/trans vinylene content on luminescence in such polymers; the living polymerisation of highly functionalised polymers in water and the regulation of the crystallisation of calcium carbonate from water by the resultant well-defined water soluble polymers; and a simple route to hyperbranched polymers and the influence of the structure and topology of the products on solution properties. In each case the influence of control of architecture on properties will be discussed.     

Cover Picture: Supramolecular Self-Assembly as a Tool To Preserve the Electronic Purity of Perylene Diimide Chromophores (Angew. Chem. Int. Ed. 12/2023)

Organic semiconductors are promising for efficient, printable optoelectronics. However, strong excited-state quenching due to uncontrolled aggregation limits their use in devices. We report on the self-assembly of a supramolecular pseudo-cube formed from six perylene diimides (PDIs). The rigid, shape-persistent cage sets the distance and orientation of the PDIs and suppresses intramolecular rotations and vibrations, leading to non-aggregated, monomer-like properties in solution and the solid state, in contrast to the fast fluorescence quenching in the free ligand. The stabilized excited state and electronic purity in the cage enables the observation of delayed fluorescence due to a bright excited multimer, acting as excited-state reservoir in a rare case of benign inter-chromophore interactions in the cage. We show that self-assembly provides a powerful tool for retaining and controlling the electronic properties of chromophores, and to bring molecular electronics devices within reach.     

The Institute for Operational Research: An Initiative to Extend the Scope of OR

One of the aims in forming the Institute for Operational Research (IOR) in 1963 was to expand the fields of application of OR and to reverse the tendency, then evident, for it to settle down as a mainly in-house, industrial activity deriving its strength from mathematics and the hard sciences, with little research content of its own. The paper outlines the early work done at IOR in pursuit of this mission, especially in multi-organizational settings such as city and regional planning, health services and the building industry. This leads into discussion of the conditions under which the work was done, the style of ‘action-research’ that evolved, its influence at the time, and its relevance to the different circumstances of the present day.     

New precision limit on the strange vector form factors of the proton

The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV2 and beam energy E(b) = 3.48 GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.     

Promotion of formaldehyde production from adsorbed methoxy by oxidation of Mo(110) with NO2

The reaction of methoxy (OCH3) in the presence of NO2 is studied on a thin-film oxide of Mo(110) for its relevance to the alkane-assisted reduction of NO(x). Temperature-programmed reaction indicates that oxygen deposited by NO2 dissociation promotes formaldehyde evolution. This pathway is not observed in any appreciable amount for methoxy on the thin-film oxide of Mo(110), nor for the reaction of methoxy in the presence of NO or O2. No new intermediates, in particular those containing C-N bonds, are detected after NO2 is exposed to the surface containing methoxy. Furthermore, infrared spectra provide evidence that the presence of NO2 does not significantly perturb the methoxy intermediate. These results indicate that surface oxidation rather than intermolecular complexation is the most likely mechanism by which NO2 promotes the evolution of oxygenates. In addition, the presence of methoxy decreases the capacity of the Mo surface to reduce NO2. No N2 is produced, and molecular desorption predominates. There are also no NO(x) species present after heating to 500 K when NO2 reacts in the presence of methoxy, whereas monomeric NO and dinitrosyl are present when NO2 reacts alone. These results are discussed in the context of CH4-assisted NO(x) reduction.