Hydroacoustic sensing of seismic events during the Tajogaite volcanic eruption (La Palma, Spain).

Volcanic processes generate a variety of seismic events that can be detected by both on-land and underwater sensors. During the 2021 subaerial eruption of the Tajogaite volcano on La Palma Island (Canary Islands, NW Africa), an underwater acoustic sensor was strategically deployed to monitor seismic activity. This study presents marine passive acoustic monitoring data from a moored hydrophone deployed offshore at a depth of 77 m and 7 km from the volcanic vent, both during and after the eruption.

Shape-responsive host-guest chemistry: metal-free tetracationic porphyrin nonplanarity promoted by clay mineral interactions assessed by theoretical simulations.

Distortions in the porphyrin core from planarity can trigger a unique structure-property relationship, imparting its basicity, chemical stability, redox potential, and excited-state energetics, among other properties. The colour change promoted by such distortion is signed by red shifts in its electronic absorption spectra. The adsorption of guest -substituted free-base porphyrin species onto inorganic hosts, such as clay minerals (layered aluminium or magnesium silicates), is known to further promote colour changes.

Theoretical UV-Vis spectra of tetracationic porphyrin: effects of environment on electronic spectral properties.

Electronic and spectroscopic properties of tetracationic 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphyrin (TMPyP) were investigated in the framework of the density functional theory (DFT). Modeling of implicit solvent, charge effects, and medium acidity were performed and compared with experimental results. Various hybrid exchange correlation functionals in the Kohn-Sham Scheme of the DFT were employed and various porphyrin models were constructed, simulating different environmental conditions.