Mit sichtbarem Licht induzierte, organische photochemische Reaktionen über Energietransferrouten

Abstract

Photokatalyse mit sichtbarem Licht ist eine sich schnell entwickelnde und wirksame Strategie zur Initiierung organischer Umwandlungen, und sie folgt den Prinzipien einer grünen und nachhaltigen Chemie. Im Allgemeinen verlaufen die Reaktionspfade der meisten durch sichtbares Licht induzierten photokatalytischen Reaktionen über einen Einelektronentransfer (single‐electron transfer, SET). Neuerdings erfahren auch Energietransferreaktionen (EnT‐Reaktionen), welche durch sichtbares Licht induziert werden, beträchtliche Aufmerksamkeit, da diese Strategie einen spezifischen Reaktionsweg aufweist und bemerkenswerte Fortschritte in diesem Feld erzielt wurden. In diesem Aufsatz diskutieren wir die neuesten Fortschritte im Bereich der durch sichtbares Licht induzierten EnT‐Reaktionen.

Nuclear Spin Singlet States in Photoactive Molecules: From Fluorescence/NMR Bimodality to a Bimolecular Switch for Spin Singlet States

“…Photoactive chemicals have received al ot of interest in recent years as ar esult of av ariety of interesting applications. [1][2][3][4][5] Among these are the utilization of photoswitches and photocages to release inactivated biological compounds at ap oint and time of interest to study,f or example,c ell processes or protein function. [1] An emerging field that operates with light-sensitive compounds is photo-pharmacology.T he latter investigates molecules that are biologically inactive but upon exposure to light can be converted into an active drug.…”

“…[1] An emerging field that operates with light-sensitive compounds is photo-pharmacology.T he latter investigates molecules that are biologically inactive but upon exposure to light can be converted into an active drug. [2] Chemical reactions can benefit from photocatalysis, [3] and fluorescent dyes are being utilized for microscopy [4] and imaging [5] applications on as ub-cellular level and even in biological tissue up to af ew millimeters in depth. Bimodal imaging approaches combining fluorescence techniques with nuclear magnetic resonance (NMR) spectroscopy were developed to leverage the excellent deep tissue contrast of NMR spectroscopy,a nd even relaxation proper-ties of contrast agents can be sped up to allow faster acquisition.…”

Photochemical Methods for Peptide Macrocyclisation

“…Moreover,w ea nticipate increased use of reactions that exploit lower energy visible light sources to induce macrocyclisation, with associated improvements in selectivity.T he reliance of many of the reactions described hereo nh ighe nergy UV irradiation is inherently limiting to functional group tolerance. [147] Photoredox catalysis driven by visible light is an important avenue to overcome this limitation, and we anticipate ag reater application of this technology to the macrocyclisation of PSPs. Other visible light-driven photochemical catalysis manifolds, such as energy transfer and photon upconversion, are also well-positioned for implementation in PSP macrocyclisation.…”

Prevent or Cure—The Unprecedented Need for Self‐Reporting Materials

“…Thea bility to trigger and control chemical reactions by light is ac ritical method in various fields in chemistry, materials science,a nd biomedicine.T his is attributed to the rather rapid associated process at ambient temperature, spatiotemporal controllability,a nd enhanced penetration depths at low energies in the visible light range (400-800 nm), which is especially critical for biomolecules to prevent undesired damage. [110][111][112][113][114] By combining photo-sensitive moieties with self-reporting properties,ap owerful tool for sensing and in situ monitoring applications is created. For example,T ang and co-workers took advantage of photosensitive aggregation-induced emission fluorogens (AIEgens), namely tetraphenylethenethiophene (TPETP) and tetraphenylsilole (TPS), with different-colored AIE (red for TPETP and green for TPS).…”