1,721,003 research outputs found
A Molecular Pump Facilitates Mechanical Adsorption Away from Equilibrium
No full textDeutsche Forschungsgemeinschaft https://doi.org/10.13039/50110000165
Visible and near-infrared light-induced photoclick reactions
No full textPhotoclick reactions combine the advantages offered by light-driven processes, that is, non-invasive and high spatiotemporal control, with classical click chemistry and have found applications ranging from surface functionalization, polymer conjugation, photocrosslinking, protein labelling and bioimaging. Despite these advances, most photoclick reactions typically require near-ultraviolet (UV) and mid-UV light to proceed. UV light can trigger undesirable responses, including cellular apoptosis, and therefore, visible and near-infrared light-induced photoclick reaction systems are highly desirable. Shifting to a longer wavelength can also reduce degradation of the photoclick reagents and products. Several strategies have been used to induce a bathochromic shift in the wavelength of irradiation-initiating photoclick reactions. For instance, the extension of the conjugated π-system, triplet-triplet energy transfer, multi-photon excitation, upconversion technology, photocatalytic and photoinitiation approaches, and designs involving photocages have all been used to achieve this goal. Current design strategies, recent advances and the outlook for long wavelength-driven photoclick reactions are presented.</p
Introduction to photoswitches and photopharmacology
No full textMartina Cacciarini, G. Andrew Woolley, Wiktor Szymanski and Nadja A. Simeth introduce the Organic & Biomolecular Chemistry and RSC Medicinal Chemistry cross-journal themed collection on ‘Photoswitches and Photopharmacology’
Substituent effects in N -acetylated phenylazopyrazole photoswitches
No full textPhenylazopyrazole photoswitches proved to be valuable structural motifs for various applications ranging from materials science to medicine. Despite their potential, their structural diversity is still limited and a larger pool of substitution patterns remains to be systematically investigated. This is paramount as electronic effects play a crucial role in the behavior of photoswitches and a deeper understanding enables their straightforward development for specific applications. In this work, we synthesized novel N -acylpyrazole-based photoswitches and conducted a comparative study with 33 phenylazopyrazoles, comparing their photoswitching properties and the impact of electronic effects. Using UV–vis and NMR spectroscopy, we discovered that simple acylation of the pyrazole moiety leads to increased quantum yields of isomerization, long Z -isomer life-times, good spectral separation, and high photostability
Optical control of pH via chromoselective photodosimetry
No full textThe precise control over the pH levels of a medium is achieved through irradiation with two different colours of light dosing photonic energy to trigger two independent chemical transformation.The dynamic regulation of pH via an external stimulus is an attractive technique to gate chemical transformations. Applying photons of different energy, we preferentially address either a photoacid or a photobase donor in the same solutions and thus, present a technique to regulate the pH of a solution through light pulses.The precise control over the pH levels of a medium is achieved through irradiation with two different colours of light dosing photonic energy to trigger two independent chemical transformation.The dynamic regulation of pH via an external stimulus is an attractive technique to gate chemical transformations. Applying photons of different energy, we preferentially address either a photoacid or a photobase donor in the same solutions and thus, present a technique to regulate the pH of a solution through light pulses.Fonds der Chemischen Industrie https://doi.org/10.13039/100018992Deutsche Forschungsgemeinschaft https://doi.org/10.13039/50110000165
Heteroaryl azo dyes as molecular photoswitches
No full textWe have known of azobenzene for over 150 years, the past 80 of which have seen the study and application of its photochromism. Azobenzene derivatives are now considered
archetypical molecular switches, and their stability and reliability make them amenable to many fields of modern chemistry , materials science, biology and photopharmacology. When developing a photoswitch for a given application, a common approach is to tune the properties of an azobenzene. It is also possible to instead use heteroaryl azo dyes — motifs that are less popular even though their diversity offers distinct features. Despite the first discoveries of switching behaviour in heteroaryl azos and azobenzenes being coincident, the former have only
recently begun to attract attention. This Review describes how the versatile and multifaceted characteristics of these scaffolds make them serious alternatives to azobenzene derivatives in molecular photoactuation. Heteroaryl azo photoswitches arguably deserve more consideration,
and our survey of these systems includes challenges to their successful deployment
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