Molecular switches
Light offers outstanding possibilities for external regulation in a plethora of applications, which are enabled by molecular photoswitches that change their properties in a reversible manner upon illumination. This Beilstein Journal of Organic Chemistry thematic issue will cover all aspects of molecular photoswitches, from their discovery, design and synthesis, through spectroscopic and computational characterization, all the way to applications in materials, biological systems, and beyond. Contributions are invited that provide new insights into all facets of this multidisciplinary topic, ranging from physical and organic chemistry all the way to the materials and life sciences.
- Full Research Paper
- Published 26 Jun 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: Light-responsive end-to-end assembly of host-functionalized gold nanorods (AuNR) by cyclodextrin–AA...
-
![]()
Scheme 2: Two-step ligand exchange reaction for the synthesis of water-soluble cyclodextrin end-functionalize...
-
![]()
Figure 1: a) ζ-Potential measurement of different stages of the ligand exchange. b) UV–vis spectroscopy befor...
-
![]()
Figure 2: UV–vis spectroscopy of a) [tCD+tTEG]AuNR with different amount of dAAP (0-35 µM). b) [tCD]AuNR with...
-
![]()
Figure 3: SPR maxima of [tCD+tTEG]AuNR with dAAP during four cycles of irradiation. a) Longitudinal SPR. b) T...
-
![]()
Figure 4: TEM-BF images of a) [tCD+tTEG]AuNR. b and c) AuNR end-to-end assemblies by dAAP (15 µM). d) Dissolv...
-
![]()
Figure 5: Reversible aggregation of [tCD+tTEG]AuNR by addition of dAAP (15 µM) monitored by dynamic light sca...
-
-
Supp. Info
- Full Research Paper
- Published 05 Jul 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Structures of diazocine platform molecules (diazocine-TATAs) 1 and 2 in cis (1a, 2a) and trans-conf...
-
![]()
Scheme 1: Synthesis route of para-diazocine platform molecule 1. a) Pd(dppf)Cl2, Cu(I)I, Et3N, 1 h, 60 °C; b)...
-
![]()
Scheme 2: Synthesis route of meta-diazocine platform 2. a) 1: KOt-Bu, THF, 3 min, 0 °C, N2; 2: Br2, 5 min, 0 ...
-
![]()
Figure 2: UV–vis spectra of 1 (left) and 2 (right) in THF at room temperature. Black: as synthesized, red: af...
-
![]()
Figure 3: STM images (30 × 30 nm², Ubias = 0.3 V, It = 40 pA) of self-assembled monolayers of (a) compound 1 ...
-
-
Supp. Info
- Full Research Paper
- Published 30 Jul 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Structures of the norbornadiene platform 1a and the quadricyclane platform 1b (for geometry coordin...
-
![]()
Scheme 1: Syntheses of the norbornadiene TATA platform 1 and TOTA platform 3. a) TMS-acetylene, Pd(PPh3)4, Cu...
-
![]()
Scheme 2: Synthesis of methylphenylnorbornadiene platform 2. a) Pd(PPh3)4, Na2CO3, toluene, EtOH, H2O, N2, re...
-
![]()
Figure 2: UV–vis spectra of platform molecules 1 (a), 2 (b) and 3 (c) (in THF at rt): Norbornadiene (black), ...
-
![]()
Figure 3: 1H NMR spectra of 1 in deuterated oxygen containing deuterated benzene (left) and degassed deuterat...
-
![]()
Figure 4: Determination of the thermal isomerization rate k of 1b (QC) by 1H NMR spectroscopy (toluene, 293.5...
-
![]()
Figure 5: (a) STM image of self-assembled monolayers of compound 1 on Au(111) (40 × 40 nm2, It = 0.05 nA, Ubi...
-
-
Supp. Info
- Letter
- Published 23 Aug 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: a) Azobenzenes A1–3 employed in this study. b) U-shaped anthracene halogen bond acceptor bearing tw...
-
![]()
Figure 1: Electrostatic potential map at different isodensity values (B3LYP/ def2/TZVP/DGZVP optimized geomet...
-
![]()
Figure 2: Top: Vertical electronic absorption spectra of a) A2 and b) A3, calculated using TD-B3LYP/def2-TZVP...
-
![]()
Figure 3: a) Space-filling model of U1···A2. The kinked alignment of both the lutidine units of U1 and the az...
-
-
Supp. Info
- Letter
- Published 13 Sep 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: Reaction mechanisms of Huisgen cyclization catalyzed by Cu(I) and Ru(I).
-
![]()
Scheme 2: Synthesis and photochromism of bisthiazolyltriazoles.
-
![]()
Figure 1: Absorption spectral change of triazoles 1o–3o upon irradiation of 313 nm light in MeCN at 28 °C. Li...
-
![]()
Scheme 3: Wavelengths of absorption maxima of the closed forms of bisthienyletenes in hexane [36].
-
![]()
Scheme 4: Photochromism of closely related compounds.
-
![]()
Figure 2: Absorption spectral change of triazoles 1c–3c during the thermal back reaction after 313-nm light i...
-
![]()
Scheme 5: Bond length (a) (in Å) and Mulliken bond order (b) of 1c–3c obtained by DFT calculations. Top numbe...
-
![]()
Scheme 6: Possible reaction mechanism of thermal ring opening of the closed forms.
-
-
Supp. Info
- Full Research Paper
- Published 16 Sep 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Selisistat (1) and hit compound GW435821X (2a).
-
![]()
Scheme 1: Reagents and conditions: a) appropriate boronic acid, Pd(PPh3)4, Na2CO3, DMF, H2O, microwave, 15 mi...
-
![]()
Scheme 2: Reagents and conditions: a) Pd2(dba)3 or Pd(OAc)2, P(o-tol)3, TEA, DMF, 120–140 °C, 0.7–24 h, 11–75...
-
![]()
Figure 2: (Left) UV–vis spectrum of 2b 50 µM in 5% DMSO (v/v) in assay buffer after varying durations of irra...
-
![]()
Figure 3: (Left) LC chromatogram of the LC–HRMS analysis of 2b after varying durations of irradiation with 25...
-
![]()
Scheme 3: Photocyclization and oxidation reaction of 2b upon UV irradiation.
-
![]()
Figure 4: Calculated and experimental absorption spectra of compounds (E)-2b-B (A), (Z)-2b-A (B), and product...
-
![]()
Scheme 4: Reagents and conditions: a) 4-fluoroaniline, oxone, HAc, 60 °C, 14 d, 42%; b) NH3, MeOH, rt, 3 d, 9...
-
![]()
Figure 5: (Left) UV–vis spectrum of 11, 50 µM in 5% DMSO (v/v), in assay buffer at the thermal equilibrium an...
-
-
Supp. Info
Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene
- Full Research Paper
- Published 20 Sep 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Synthetic procedure for a diarylethene (1o).
-
![]()
Figure 2: Photochromic reaction of diarylethene 1o having an ESIPT moiety.
-
![]()
Figure 3: Absorption spectral changes of diarylethene 1o having an ESIPT moiety in THF (c = 1.3×10-5 M). Blac...
-
![]()
Figure 4: Fluorescent spectra of 1o in several solvents (λex = 370 nm). Hexane (black line), chloroform (red ...
-
![]()
Figure 5: (a) The energy diagram of the ESIPT process of 1. (b) ESIPT fluorescence quenching upon UV light (λ...
-
![]()
Figure 6: (a) Fluorescence photographs of solutions/suspensions of 1o (1.2×10-4 M) in THF/water mixtures with...
-
![]()
Figure 7: (a) Crystals of 1o before UV light irradiation, (b) Green fluorescence of 1o observed under UV ligh...
-
-
Supp. Info
- Full Research Paper
- Published 04 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: Photochromic reaction schemes of (a) PIC and (b) Benzil-PIC.
-
![]()
Figure 1: Absorption spectra of PIC, benzil, and the two isomers of Benzil-PIC in benzene at 298 K. The inset...
-
![]()
Figure 2: Nanosecond-to-microsecond transient absorption spectra of Benzil-PIC in benzene under (a) argon and...
-
![]()
Figure 3: Femtosecond-to-nanosecond transient absorption spectra of (a) benzil and (b) Benzil-PIC (right) in ...
-
![]()
Figure 4: Phosphorescence spectra of benzil at 77 K and 100 K and that of PIC at 77 K in EPA. A blue solid li...
-
![]()
Figure 5: Energy diagram of the visible-light sensitized photochromic reaction of Benzil-PIC.
-
![]()
Scheme 2: Synthetic procedure of Benzil-PIC (analogous to synthesis of PIC in [24]).
-
-
Supp. Info
- Full Research Paper
- Published 07 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: The structure (A) of reporter Glyco-DTE and working principle (B) of photochromic glycosheet Glyco-...
-
![]()
Scheme 2: Synthetic route to dithienylethene fluorescence reporters Glyco-DTE and 8o. VcNa: sodium ascorbate.
-
![]()
Figure 1: Absorption spectral changes (A), absorption fatigue resistance (B), emission spectral changes (C) a...
-
![]()
Figure 2: (A) The absorbance spectrum and (B) high resolution TEM image of 2D MnO2 nanosheets (1 × 10−5 g/mL)...
-
![]()
Figure 3: (A) Emission spectral changes of reporter Glyco-DTE (1 × 10−5 mol/L in PBS buffer, 0.25‰ Triton X-1...
-
![]()
Figure 4: (A) Fluorescence imaging of HepG2 cells and HeLa cells after incubated with reporters Glyco-DTE (20...
-
![]()
Figure 5: (A) Fluorescence imaging of HepG2 cells and HeLa cells after incubated with Glyco-DTE@MnO2 photochr...
-
-
Supp. Info
- Full Research Paper
- Published 10 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: Reversible photoisomerization of phenylazotrimethylpyrazole 1.
-
![]()
Figure 1: 1H NMR spectrum of (E-1)2
![[Graphic 1]](/bjoc/content/inline/1860-5397-15-232-i3.svg?max-width=637&scale=1.18182)
2 (500 MHz, D2O, 298 K).
-
![]()
Figure 2: Partial 1H-1H NOESY NMR spectrum of (E-1)2
2 showing NOE correlations between host 2 and guest 1 (50...
-
![]()
Figure 3: Front view (a) and side view (b) of the X-ray crystal structure of (E-1)2
2 (major conformations of 1...
-
![]()
Figure 4: UV–vis absorption spectrum of an aqueous solution of (E-1)2
2 (blue) and following exposure of this ...
-
![]()
Figure 5: Top view (a) and side view (b) of the energy-optimized structure of (Z-1)
2. Color codes: C, gray; N...
-
![]()
Figure 6: A series of 1H NMR spectra of (E-1)2
2 (500 MHz, D2O, 298 K) before (bottom) and after exposure to U...
-
![]()
Figure 7: 1H NMR and 1H DOSY spectra of (E-1)2
2 (500 MHz, D2O, 298 K) before (left) and after (center) UV irr...
-
![]()
Figure 8: Palladium-accelerated back-isomerization of Z-1. a) Kinetics of the thermal back-isomerization of Z-...
-
-
Supp. Info
- Full Research Paper
- Published 11 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: The stiff stilbene photoisomerization from Z to E and vice versa by irradiation at 300 nm and 360 n...
-
![]()
Figure 1: The investigated SS-macrocycles (Z)-1a–d.
-
![]()
Scheme 2: Synthetic route to SS-macrocycles. i. (1) Triflic acid (3 equiv), DCM (dry), Ar atmosphere, MW (110...
-
![]()
Scheme 3: The photoisomerization of the stiff stilbene macrocycles, showing the stretching of the linker (gre...
-
![]()
Scheme 4: Noncyclic stiff stilbene diester 7 used as reference in the photoisomerization study.
-
![]()
Figure 2: The photoisomerization of the SS-macrocycles shows a clear correlation between the Z/E ratio in the...
-
![]()
Figure 3: Gibbs free energy differences (ΔG) between Z- and E-isomers of 1a–d and of the reference compound 7...
-
![]()
Figure 4: Ring strain for E and Z-isomers of 1a–d expressed as the Gibbs free energy difference to an acyclic...
-
![]()
Figure 5: The differences in ring strain between the E- and Z-isomers show an exponential correlation to the ...
-
![]()
Figure 6: Conformer ensembles for the macrocyclic stiff stilbene diethers 1a–d. Dihedral angles between the t...
-
![]()
Figure 7: Distances derived from NOE buildup experiments. Distances between pairs of protons or groups of pro...
-
![]()
Figure 8: Numbering of carbons in compounds 6a–d, showing 6d as an example.
-
![]()
Figure 9: Numbering of carbons in compounds (Z)-1a–d, showing (Z)-1d as an example.
-
-
Supp. Info
- Letter
- Published 15 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Families of diarylethene-bases ligands with spatial proximity of coordination site (blue) and photo...
-
![]()
Scheme 1: Synthesis of photochromic ligands.
-
![]()
Figure 2: Electronic spectra of diarylethene 6 upon UV irradiation (313 nm, toluene, c = 3.4 × 10−5 M). Inset...
-
![]()
Scheme 2: Reversible photocyclization of ligand 6.
-
![]()
Figure 3: Molecular structure of complexes 8 (top) and 9 (bottom) at 100 K. The H atoms are omitted for clari...
-
![]()
Figure 4: Variable temperature χT product (blue) and χ (green) of 8 (top) and 9 (bottom) measured at an exter...
-
-
Supp. Info
- Full Research Paper
- Published 15 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: a) The photoinduced Z/E isomerization of hydrazone 1, and accompanied changes in b) UV–vis absorpti...
-
![]()
Figure 2: Fluorescence decays (dots) in the 500–520 nm spectral region (emission range of the Z-isomer) for 1...
-
![]()
Figure 3: Fluorescence decays (dots) in the 500–520 nm spectral region (red; induced Z-emission), and in the ...
-
![]()
Figure 4: a) Transient absorption data recorded for hydrazone 1 in toluene upon excitation at 400 nm; b) EADS...
-
![]()
Figure 5: EADS obtained by global fit of the transient data recorded in a) acetonitrile and b) methanol upon ...
-
![]()
Figure 6: Kinetic traces recorded at the maximum of the excited state absorption band in toluene, acetonitril...
-
![]()
Figure 7: a) Transient absorption spectra measured for hydrazone 1 in toluene upon excitation at 785 nm. b) C...
-
-
Supp. Info
- Full Research Paper
- Published 18 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Scheme 1: PSHD photochromism [10].
-
![]()
Figure 1: Proposed gating of sensitivity to photoinduced charge transfer by a photochromic photooxidant in wh...
-
![]()
Scheme 2: QSHD photochromism [21].
-
![]()
Figure 2: Cyclic voltammograms of a) 1b before irradiation or electrolysis (solid blue), b) 1b/2b after 25 sc...
-
![]()
Figure 3: Cyclic voltammograms of a) 3b (with trace 5b) before irradiation or electrolysis (solid blue), b) 3b...
-
![]()
Figure 4: Cyclic voltammograms of a) 3a before irradiation or electrolysis (solid blue), b) 3a + 5a after 25 ...
-
![]()
Figure 5: 1H NMR distinction between SW 3a, thermal/eLW 5a, and pLW 4a, in acetone-d6, as observed a) before ...
-
![]()
Figure 6: HOMO (MO 105, red and blue) and LUMO (MO 106, green and yellow) computed for 3a in its ground (S0) ...
-
![]()
Scheme 3: Proposed mechanism for differential formation of pLW (4) and eLW (5) from SW (3).
-
![]()
Figure 7: Frontier orbital occupancies of relevant electronic states of 3a. Note: the photochemical excited s...
-
-
Supp. Info
- Letter
- Published 22 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: A) Structure of the pioneering azobenzene-modified DNA [16] compared with the photoswitchable PNA struc...
-
![]()
Scheme 1: Solid-phase synthesis of photoswitchable PNAs; Aeg = N-(2-aminoethyl)glycine, Bhoc = benzhydryloxyc...
-
![]()
Figure 2: Time-dependent conversion to the thermodynamically stable isomer of PNA12(oF4Azo) (3; green triangl...
-
![]()
Figure 3: A) Melting curves of a 1 µM duplex solution in phosphate buffer (10 mM NaH2PO4, 150 mM NaCl, pH 7.4...
-
![]()
Figure 4: Outline of the displacement assay principle, in which a photoswitchable PNA probe (blue) hybridizes...
-
![]()
Figure 5: Time-dependent fluorescence signals from two independent experiments at 520 nm of 0.75 μM FAM/BHQ-d...
-
-
Supp. Info
- Full Research Paper
- Published 23 Oct 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Design of the CXCR3 efficacy photowitchable ligands. A,B) Schematic representation of a GPCR photoc...
-
![]()
Figure 2: Conformational alignment of a biaryl CXCR3 agonist with a designed azobenzene analogue. A) 2D struc...
-
![]()
Scheme 1: Synthetic strategies for compounds 2a–e, 3a–e, 4a–d, 4f–i and 5b,c (Y = H, Cl). Reagents and condit...
-
![]()
Scheme 2: Synthetic strategies for compounds 3f–h, 4e, 6b, and 6d (Y = H, F, Cl, Br). Reagents and conditions...
-
![]()
Figure 3: Comparison of compounds belonging to the subseries 3 or 4 with a halogen substitution on the ortho-...
-
![]()
Scheme 3: Synthetic strategy for compound 6e. Reagents and conditions: (a) i) K2CO3 (2.0 equiv), DMF, µW, 65 ...
-
![]()
Scheme 4: Synthetic strategies for compounds 6f–h (Y = OMe, OiPr, SMe). Reagents and conditions: (a) NaOMe or...
-
![]()
Figure 4: Properties of subseries 3e, 4d, 6b and 6d-h. (A) UV–vis absorption spectra of (top) trans-isomers o...
-
-
Supp. Info
- Full Research Paper
- Published 11 Nov 2019
-
PDF -
Album-
![]()
Graphical Abstract
-
![]()
Figure 1: Top: photoisomers of diarylethene 1, bottom: spectral overlaps between the 1-o (black line), 1-c (r...
-
![]()
Figure 2: UCNPs (black dots) are irradiated inside the cylindrical CW 976 nm laser beam. Absorbed laser power...
-
![]()
Figure 3: Kinetic trace at 650 nm under CW 976 nm laser at 4.71 W. Initial slope (red line) was determined on...
-
-
Supp. Info
