Tailoring of organic dyes with oxidoreductive compounds to obtain photocyclic radical generator systems exhibiting photocatalytic behavior

• Christian Ley,
• Julien Christmann,
• Ahmad Ibrahim,
• Luciano H. Di Stefano and
• Xavier Allonas

Beilstein J. Org. Chem. 2014, 10, 936–947, doi:10.3762/bjoc.10.92

• cell. Laser flash photolysis experiments (LFP) were carried out exciting at 532 nm with a nanosecond Nd-YAG laser (Powerlite 9010, Continuum), operating at 10 Hz. The transient absorption analysis system (LP900, Edinburgh Instruments) uses a 450 W pulsed Xe arc lamp, a Czerny–Turner monochromator, a

Substituent effect on the energy barrier for σ-bond formation from π-single-bonded species, singlet 2,2-dialkoxycyclopentane-1,3-diyls

• Jianhuai Ye,
• Yoshihisa Fujiwara and
• Manabu Abe

Beilstein J. Org. Chem. 2013, 9, 925–933, doi:10.3762/bjoc.9.106

• photolysis in a MTHF glass were thermally persistent at 80 K and resembled that of the transient absorption spectra in solution (for example, DRe, λmax = 590 nm, Figure 2b); (b) the species were ESR-silent in the MTHF-matrix at 80 K; (c) the lifetime of the transient was insensitive to the presence of

• . Localized singlet diradicals. (a) Absorption spectrum of the singlet diradical DRe in a MTHF matrix at 80 K; (b) transient absorption spectrum of AZe measured immediately after the laser pulse (λexc = 355 nm); (c) transient decay trace at 580 nm and 20 °C. Alkoxy group effect on the lifetime of π-single

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

• Jaume García-Amorós and
• Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

• -azobenzene derivatives. This notable red-shift of the absorption wavelength arises from the strong charge transfer from the alkoxy group to the positively-charged nitrogen atom of the pyridinium salt. Figure 8 shows the transient absorption generated upon pulsed laser irradiation of ethanol solutions of azo

• -trans isomerisation processes of azobenzenes. Effect of the presence of the electron-withdrawing cyano and nitro groups on the thermal relaxation time in ethanol at 298 K, τ, for the type-I azoderivatives 5 and 6. Transient absorption generated by UV irradiation (λ = 355 nm) for azo-dyes 8 (right) and 9

Synthesis of novel photochromic pyrans via palladium- mediated reactions

• Christoph Böttcher,
• Gehad Zeyat,
• Saleh A. Ahmed,
• Elisabeth Irran,
• Thorben Cordes,
• Cord Elsner,
• Wolfgang Zinth and
• Karola Rueck-Braun

Beilstein J. Org. Chem. 2009, 5, No. 25, doi:10.3762/bjoc.5.25

• its “ring-opened” forms. The photoreaction was initiated by short light-pulses at 340 nm. The corresponding transient absorption changes (375–650 nm) as a function of the delay-time between pump and probe are shown in Figure 1a. An inspection of the data at early delay-times (0.2 ps) reveals a broad