Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• -based photoprobes require asymmetric substitution of the photochrome, we decided to explore the effects of changing one para substituent of 4FAB so as to allow the attachment of different substituents from our first 4FAB photoprobe [14]. Specifically, we were attracted by the application [15] of a

• . Since the latter has an oxygen atom para to the azo group we tested the feasibility of adding such a strong electron donor to an analog of a difluoro-(2F)AB Hecht photochrome [13] by making "MeO-2FAB" (Figure 1, see Supporting Information File 1 for synthesis). Since 2FAB and 4FAB photochromes with

• in Figure 1). Our data is similar to that recently reported by Gorostiza and co-workers for a monofluorinated AB photochrome [18] (core structure shown in Figure 1 as "1FAB"). This monofluoro-(1)FAB chromophore is much less electron rich than MeO-2FAB, so it is perhaps not surprising that 2FAB cannot

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• -switchable binding sites. Conclusion In conclusion, a photochromic BAPTA-based calcium ion host (1) incorporating an azobenzene photochrome is described. This chelating molecule showed high affinity for Ca2+ under pseudo-physiological conditions (Kd = 0.102 μM) and showed efficient photochemical trans-to-cis

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• ordered monolayers on Au(111) surfaces. Keywords: cis–trans isomerization; diazocine; molecular switch; photochrome; self-assembled monolayers; TATA platform; Introduction Catalysts increase chemical reaction rates by lowering the activation energies and thus create more favorable reaction pathways [1

Synthesis of functionalized diazocines for application as building blocks in photo- and mechanoresponsive materials

• Widukind Moormann,
• Daniel Langbehn and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 727–732, doi:10.3762/bjoc.15.68

• molecular switches in photo and mechanoresponsive macromolecules and other smart materials. Keywords: bridged azobenzene; diazocine; mechanophor; oxidative C–C coupling; photochrome; reductive azo cyclization; Introduction The field of photoresponsive materials is of growing interest [1][2][3]. Several

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• multichromophoric glucopyranoside 2 bearing three dicyanomethylenepyran (DCM) fluorophores and one diarylethene (DAE) photochrome has been prepared by Cu(I)-catalyzed alkyne–azide cycloaddition reaction. The fluorescence of 2 was switched off upon UV irradiation, in proportion with the open to closed form (OF to CF

• (photochrome and fluorophore) moieties have also been reported by other groups [5][6][7][8][9]. The fluorophore vs photochrome ratio in reported bifunctional systems is 1:1 [4][5][6][7] or 2:1 [8][9]. Other strategies to assemble interacting fluorophores and photochromes (supramolecular systems, nanoparticles

• fluorophores and a DAE photochrome on the methyl α-D-glucopyranoside in good yield. The multichromophoric compound 2 can be reversibly switched upon UV and visible irradiation, and showed an excellent fatigue resistance. Under UV irradiation at 335 nm, the fluorescence was decreased by 51%. This value