Introduction of the year 2020

Herein we introduce the volume and its three parts: critical reviews, highlights on recent topics and finally SPR lectures in photochemistry. We then summarize the most significant advancements in photochemistry in 2020 by presenting awards, special issues, handbooks and some representative examples of the new discoveries in the field. </p

Aryl–Cl vs heteroatom–Si bond cleavage on the route to the photochemical generation of σ,π-heterodiradicals

The photochemistry of aryl chlorides having a X-SiMe3 group (X = O, NR, S, SiMe2) tethered to the aromatic ring has been investigated in detail, with the aim to generate valuable ϭ,π-heterodiradicals. Two competitive pathways arising from the excited triplet state of the aromatics have been observed, namely heterolysis of the aryl–chlorine bond and homolysis of the X–silicon bond. The former path is found in chlorinated phenols and anilines, whereas the latter is exclusive in the case of silylated thiophenols and aryl silanes. A combined experimental/computational approach was pursued to explain such a photochemical behavior. Graphical abstract[Figure not available: see fulltext.

Correction: Role of solute-solvent hydrogen bonds on the ground state and the excited state proton transfer in 3-hydroxyflavone. A systematic spectrophotometric study

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Metal-free photocatalytic cross-electrophile coupling enables C1 homologation and alkylation of carboxylic acids with aldehydes

Authors are grateful to have received generous funding from the European Union H2020 research and innovation program under the Marie S. Curie Grant Agreement (PhotoReAct, No 956324, S.B., M.L., A.L., G.M., E.Z.C., T.N.; CHAIR, No 860762, A.P., M.J., T.N.)In contemporary drug discovery, enhancing the sp3-hybridized character of molecular structures is paramount, necessitating innovative synthetic methods. Herein, we introduce a deoxygenative cross-electrophile coupling technique that pairs easily accessible carboxylic acid-derived redox-active esters with aldehyde sulfonyl hydrazones, employing Eosin Y as an organophotocatalyst under visible light irradiation. This approach serves as a versatile, metal-free C(sp3)−C(sp3) cross-coupling platform. We demonstrate its synthetic value as a safer, broadly applicable C1 homologation of carboxylic acids, offering an alternative to the traditional Arndt-Eistert reaction. Additionally, our method provides direct access to cyclic and acyclic β-arylethylamines using diverse aldehyde-derived sulfonyl hydrazones. Notably, the methodology proves to be compatible with the late-stage functionalization of peptides on solid-phase, streamlining the modification of intricate peptides without the need for exhaustive de-novo synthesis.Peer reviewe

Generation of Alkyl Radicals:From the Tyranny of Tin to the Photon Democracy

Alkyl radicals are key intermediates in organic synthesis. Their classic generation from alkyl halides has a severe drawback due to the employment of toxic tin hydrides to the point that "flight from the tyranny of tin"in radical processes was considered for a long time an unavoidable issue. This review summarizes the main alternative approaches for the generation of unstabilized alkyl radicals, using photons as traceless promoters. The recent development in photochemical and photocatalyzed processes enabled the discovery of a plethora of new alkyl radical precursors, opening the world of radical chemistry to a broader community, thus allowing a new era of photon democracy

Lung anatomy, energy load, and ventilator-induced lung injury

High tidal volume can cause ventilator-induced lung injury (VILI), but positive end-expiratory pressure (PEEP) is thought to be protective. We aimed to find the volumetric VILI threshold and see whether PEEP is protective per se or indirectly

Recent advances in the development of high-resolution 3D cadmium zinc telluride drift strip detectors

In the last two decades, great efforts have been made in the development of 3D cadmium-zinc-Telluride (CZT) detectors operating at room temperature for gamma-ray spectroscopic imaging. This work presents the spectroscopic performance of new high-resolution CZT drift strip detectors, recently developed at IMEM-CNR of Parma (Italy) in collaboration with due2lab (Italy). The detectors (19.4 mm × 19.4 mm × 6 mm) are organized into collecting anode strips (pitch of 1.6 mm) and drift strips (pitch of 0.4 mm) which are negatively biased to optimize electron charge collection. The cathode is divided into strips orthogonal to the anode strips with a pitch of 2 mm. Dedicated pulse processing analysis was performed on a wide range of collected and induced charge pulse shapes using custom 32-channel digital readout electronics. Excellent room-Temperature energy resolution (1.3% FWHM at 662 keV) was achieved using the detectors without any spectral corrections. Further improvements (0.8% FWHM at 662 keV) were also obtained through a novel correction technique based on the analysis of collected-induced charge pulses from anode and drift strips. These activities are in the framework of two Italian research projects on the development of spectroscopic gamma-ray imagers (10-1000 keV) for astrophysical and medical applications

Development of a 3D CZT Spectrometer System with Digital Readout for Hard X/Gamma-Ray Astronomy

We report on the development and of a complete X/γ rays detection system (10-1000 keV) based on CZT spectrometers with spatial resolution in three dimensions (3D) and a digital electronics acquisition chain. The prototype is made by packing four linear modules, each composed of one 3D CZT sensors. Each sensors is realized using a single spectroscopic graded CZT crystal of about 20×20×5 mm3. An electrode structure consisting of 12 collecting anodes with a pitch of 1.6 mm and 3 drift strips between each pair of anodes for 48 strips (0.15 mm wide) on the anodic side was adopted. The cathode is made of 10 strips with a pitch of 2 mm and orthogonal to anode side strips. Since the reading of the drift strips will carried out by putting in parallel all the strips that occupy the same place with respect to a collecting anode, the channels number for each sensors is only 25. The detector readout front-is based on custom designed low noise charge sensitive pre-amplifiers (CSP) implemented in hybrid 16 channels board. The CZT module and its CSP front-end provide the signals to a multichannel Digital Pulse Processing FPGA based system able to digitize and process continuously the signals. The digital system implement an innovative firmware that allow performing fine time-tagging, online pulse shape and height analysis with good energy resolution