This work presents the formulation and characterization of a new product for the protection of outdoor frescoes from aggressive environmental agents. The formulation is designed as an innovative green coating, prepared through a zero-waste one-pot-synthetic method to form silver nanoparticles (AgNPs) directly in a chitosan-based medium. The AgNPs are seeded and grown in a mixed hydrogel of chitosan, azelaic, and lactic acid, by the reduction of silver nitrate, and using calcium hydroxide as precipitating agent. The rheological properties of this coating base are optimized by the addition of a solvent mixture of glycerol and ethanol with a 1:1 volume ratio. The new formulation and two commercial products (Paraloid^® B72 and Proconsol^®) are then applied by brush to ad hoc mock-ups to be evaluated for chemical stability, color and gloss variations, morphological variation, hydrophobicity, and water vapor permeability via Fourier-transform infrared spectroscopy (FT-IR) in attenuated total reflection (ATR) mode, spectrophotometer analysis, stereomicroscope observations, UNI EN 15802, and UNI EN 15803, respectively. The results show that the application of the hybrid chitosan-AgNPs coating is promising for the protection of outdoor frescoes and that it can underpin the development of new products that address the lack of conservation strategies specifically designed for wall painting.

Two different types of spectroscopic methods, namely diffuse reflection infrared spectroscopy (DRIFTS) as a vibrational spectroscopy and ion-beam-induced luminescence (IBIL) as an optical spectroscopy, have been exploited for the analysis of three sand samples collected from the Adige, Bacchiglione, and Brenta rivers (Veneto, Northern Italy) with the aim to set up a procedure for the comparison of the relative abundance of silicates, carbonates, and feldspars. By fitting the spectra, the features corresponding to different geological compounds have been identified and descriptive indexes of their relative amount have been obtained by comparing the peak area ratios.

The present work deals with the computational study of HC₃N$··$HCN$··$H₂C₂-, (HC₃N)₂$··$H₂C₂-, and HC₃N$··$(H₂C₂)₂-mixed trimers. The different equilibrium structures of the different low-lying minima on the corresponding potential energy surface (PES) were accurately determined, and the relative stabilities were computed by extrapolation procedures to the complete basis set limit. For each mixed trimer, the non-covalent interactions ruling the structure of the most stable isomer were analyzed using the QTAIM (Quantum Theory of Atoms in Molecules) approach. Additional insights into these interactions were provided by the Natural Bond Orbital (NBO) and Symmetry-Adapted Perturbation Theory (SAPT) methods. These results can be used to assist further theoretical investigations and experimental studies on the formation of larger molecules potentially relevant in astrochemistry.