Triplet sensitization enables bidirectional isomerization of diazocine with 130 nm redshift in excitation wavelengths

Abstract

Diazocines are bridged azobenzenes with phenyl rings connected by a CH2-CH2 group. Despite this rather small structural difference, diazocine exhibits improved properties over azobenzene as a photoswitch and most importantly,...

A general method for near-infrared photoswitching in biology, demonstrated by the >700 nm photocontrol of GPCR activity in brain slices

“…There are only ten significant experimental reports in this area (Figure 1b; Supporting Note 2). 26,[28][29][30][31][32][33][34] Though the desirability of TET-based Z→mostly-E isomerisation at wavelengths decoupled from azobenzene's own absorption is clear, 32 these systems could not be generally applied (Supporting Note 3). In brief, this is because they were intermolecular schemes, requiring collisional TET to the azobenzene without TET to competitive quenchers e.g.…”

Photoswitchable imines: aryliminopyrazoles quantitatively convert to long-lived Z-isomers with visible light

“…16 Of the various classes of photoswitches, 17,18 those that display a photoinduced trans – cis ( E / Z ) isomerism are arguably the most commonly studied. 3,19–24 Examples of such switches include derivatives of stilbene (CC), 25,26 azobenzene and diazocine (NN), 19–21,27,28 and subsets of imines (CN) that include hydrazones 29 and acylhydrazones. 22,30 Imines, specifically sterically hindered benzil-derived imines, 31 ketimines 32–34 and iminothioindoxyls 3,35 have shown promise as photoswitches and light-activated molecular motors that display unidirectional rotation about the imine bond.…”

Detour to success: photoswitching via indirect excitation

“…Triplet sensitisation is relatively universal as the triplet energy of azobenzenes is relatively unperturbed by structural modifications. 50 However, azoheteroarenes such as arylazopyrazoles 51 and the Z isomer of diazocines (bridged azobenzenes) 52 exhibit considerably higher triplet energies than conventional azobenzene or the corresponding E isomers. This may be an obstacle to using low-energy light but also an asset when selective sensitisation of either isomer is desired.…”

“…PSS isomer distributions of 49% E and >99% Z could be acquired upon excitation with 530 and 740 nm, respectively. 52 The other special case of triplet-sensitised photoswitching leads to the metastable isomer exclusively, a previously unattained feat. The DESC approach ( Fig.…”