Fastest molecular photochromic switches based on nanosecond isomerizing benzothiazolium azophenolic salts

Visible‐Light‐Activated Molecular Switches

“…As aresult, the p!p*bands are red-shifted in the 400-600 nm region and concomitantly the thermal stability of the Z isomers decreases,and these two effects become more pronounced with the strength of the donor/acceptor substituents.T ypically,a mino azobenzenes such as 4 can still be switched with light in both directions via their p!p*and n!p*excitations,and are stable for minutes to hours,whereas in the push-pull class,the p!p*and n!p* bands totally overlap and t 1/2 typically ranges from nanoseconds [36] to seconds.B is(amido) azobenzenes 4 have recently been used in the context of light-gated ion channels [37] or introduced into rigid aromatic backbones for the construction of optomechanical gels that are able to reversibly bend upon alternating irradiation with blue (442 nm) and green (> 490 nm) light, [38] while derivatives of so-called "disperse-red" (compound 5;R = (CH 2 ) 2 OH) have been extensively used in recent decades for photo-inducing motion in polymer materials. As aresult, the p!p*bands are red-shifted in the 400-600 nm region and concomitantly the thermal stability of the Z isomers decreases,and these two effects become more pronounced with the strength of the donor/acceptor substituents.T ypically,a mino azobenzenes such as 4 can still be switched with light in both directions via their p!p*and n!p*excitations,and are stable for minutes to hours,whereas in the push-pull class,the p!p*and n!p* bands totally overlap and t 1/2 typically ranges from nanoseconds [36] to seconds.B is(amido) azobenzenes 4 have recently been used in the context of light-gated ion channels [37] or introduced into rigid aromatic backbones for the construction of optomechanical gels that are able to reversibly bend upon alternating irradiation with blue (442 nm) and green (> 490 nm) light, [38] while derivatives of so-called "disperse-red" (compound 5;R = (CH 2 ) 2 OH) have been extensively used in recent decades for photo-inducing motion in polymer materials.…”

Advances in understanding the photoresponsive behavior of azobenzenes substituted with strong electron withdrawing groups

“…Azobenzene and its derivatives are fascinating molecules that have numerous applications in the field of nonlinear optics [1][2][3][4][5], surface relief gratings [1,6], photoswitching [7], optical data storage [8], photoprobes [9] and liquid crystals alignment [10]. The key to the interesting applications of azobenzenes is the facile and reversible isomerization of the azo bond, between the more thermally stable E configuration and the meta-stable Z form [11][12][13][14][15].…”

A Directly Writable Photochromic Bisthienylethene

“…Photochromic compounds undergo reversible geometrical and electronic structural changes between two isomers upon light irradiation. Due to the unique properties associated with reversible structural and optical switching, photochromic compounds have been extensively used in the development of various optoelectric devices, including optical memory devices, molecular switches, and molecular wires, as well as the development of solar energy storage, optical switching sensitizers for dye‐sensitized solar cells, and organic photochromic lenses…”