Evidence for an Oxygen Anthracene Sandwich Complex

Abstract

Oxygen sticks in between acenes: The rate of the photooxygenation of bis(anthryl)alkanes with singlet oxygen shows a maximum for a defined chain length (n=4). In combination with calculations, a bathochromic shift of the UV/Vis absorption for only one endoperoxide and a CT absorption band, this gives considerable evidence for an oxygen anthracene sandwich complex.

Reactivity of a pyridinium-substituted dimethyldihydropyrene switch under aerobic conditions: self-sensitized photo-oxygenation and thermal release of singlet oxygen

“…1-14 This objective may be achieved by the use of specific polyaromatic compounds (often based on the 1,4-dimethylnaphthalene and 9,10diphenylanthracene motifs 11,12,[15][16][17][18][19][20][21][22][23][24] ) that can be converted to endoperoxides (EPOs) through a formal [4+2] cycloaddition reaction when irradiated with light in the presence of an external photosensitizer (e.g. methylene blue or porphyrin derivatives).…”

A Rational Approach to Tetra‐Functional Photo‐Switches

“…NMR spectra were recorded on a Bruker Avance III 300, a Bruker DRX 500, a Bruker Avance III 500, a Bruker Avance III 500 HD and a Bruker Avance 600 at ambient temperature (298 K). The chemical shifts (δ) were measured in ppm with respect to the solvent [CDCl 3 : 1 H NMR δ = 7.26 ppm, 13 C NMR δ = 77.16 ppm; C 6 D 6 : 1 H NMR δ = 7.16 ppm, 13 C NMR δ = 128.06 ppm; o-Cl 2 C 6 D 4 (from deutero): 1 H NMR δ = 6.93 and 7.19 ppm] or referenced externally ( 29 Si: SiMe 4 , 119 Sn: SnMe 4 ). EI mass spectra were recorded using an Autospec X magnetic sector mass spectrometer with EBE geometry (Vacuum Generators, Manchester, UK) equipped with a standard EI source.…”

“…The cyclomers 8 PC , 9 PC , 11 PC and 13 PC were further characterized by 13 C NMR spectroscopy and by (high) resolution mass spectrometry. Their molecular structures in the crystalline state were determined by X-ray diffraction studies and are depicted in Figure 2 (for details see SI).…”

“…1 3.00 (s, 4H, CH 2 CH 2 ) ppm. 13 3 J H,H = 7.9 Hz, 4H, H4/H5), 7.00 (d, 3 J H,H = 7.9 Hz, 4H, H2/H7), 6.82 (t, 3 J H,H = 7.9 Hz, 4H, H3/H6), 6.09 (s, 2H, H9), 2.70 (t, 3 J H,H = 6.1 Hz, 4H, CH 2 CH 2 CH 2 ), 2.42 (p, 3 J H,H = 6.1 Hz, 2H, CH 2 CH 2 CH 2 ) ppm. 13 3 J H,H = 7.9 Hz, 4H, H4/H5), 6.83 (d, 3 J H,H = 7.9 Hz, 4H, H2/H7), 6.68 (t, 3 J H,H = 7.9 Hz, 4H, H3/H6), 6.12 (s, 2H, H9), 2.48 (t, 3 J H,H = 5.…”

“…13 3 J H,H = 7.9 Hz, 4H, H4/H5), 7.00 (d, 3 J H,H = 7.9 Hz, 4H, H2/H7), 6.82 (t, 3 J H,H = 7.9 Hz, 4H, H3/H6), 6.09 (s, 2H, H9), 2.70 (t, 3 J H,H = 6.1 Hz, 4H, CH 2 CH 2 CH 2 ), 2.42 (p, 3 J H,H = 6.1 Hz, 2H, CH 2 CH 2 CH 2 ) ppm. 13 3 J H,H = 7.9 Hz, 4H, H4/H5), 6.83 (d, 3 J H,H = 7.9 Hz, 4H, H2/H7), 6.68 (t, 3 J H,H = 7.9 Hz, 4H, H3/H6), 6.12 (s, 2H, H9), 2.48 (t, 3 J H,H = 5. 9 Hz, 4H, CH 2 CH 2 CH 2 ), 2.23 (p, 3 Monitoring the photo-cyclomerization of 19 to 19 PC by UV/VIS spectroscopy was performed by irradiating a solution of 19 in dichloromethane (2.5 × 10 À 5 mol L À 1 ) in an absorption cell with PTFE stopper (10.00 mm, 200-3500 nm) and recording absorption spectra in defined time intervals (0, 0.25, 0.5, 1, 2 and 4 minutes).…”