Charge-Transfer Complexes: Halogen-Doped Anthracene as a Case of Study.

Charge transfer (CT) crystals exhibit unique electronic and magnetic properties with interesting applications. We present a rational and easy guide which allows to foresee the effective charge transfer co-crystal production and that is based on the comparison of the frontier molecular orbital (MO) energies of a donor and acceptor couple. For the sake of comparison, theoretical calculations have been carried out by using the cheap and fast PM6 semiempirical Hamiltonian and pure HF/cc-pVTZ level of the theory. The results are then compared with experimental results obtained both by chemical (bromine and iodine were used as the acceptor) and electrochemical doping (exploiting an original experimental set-up by this laboratory: the electrochemical transistor). Infra-red vibrational experimental results and theoretically calculated spectra are compared to assess both the effective donor-acceptor (D/A) charge-transfer and transport mechanism (giant IRAV polaron signature). XPS spectra have been collected (carbon (1 s) and iodine (3d5/2)) signals, yielding further evidence of the effective formation of the CT anthracene:iodine complex.

The heat pumps for better urban air quality✰.

Strict restrictions to halt the spread of COVID-19 provided an opportunity to quantify the contribution of different pollution agents. We analyze the concentrations of pollutants recorded in Rome during the lockdown periods for the containment of the spread of Covid 19, compared with those of other periods and years. We recorded a significant contribution attributable to heating systems powered by fuel. Thus, we propose the replacement of existing boilers for heating and drinking hot water (DHW) production systems, with air / water heat pumps, as an intervention to improve urban air quality. We analyze the replacement scenarios, within the entire residential building stock in the Municipality of Rome, in terms of emissions reduction, primary energy savings and reduced CO2 production. Results show significant reductions in concentrations. Reduction in primary energy consumption varies between 12% and 56% for various scenarios, different for outdoor temperatures and mix of electricity generation. The intervention on the urban scale can reduce air pollution on a long-term basis, implying significant reductions of polluting emissions in urban areas, and entailed reduced energy (and therefore environmental) costs, with a significant step towards sustainable cities.