Extremely reactive carbon-carbon double bonds-I

Spiroconjugated Donor−σ–Acceptor Charge-Transfer Dyes: Effect of the π-Subsystems on the Optoelectronic Properties

“…1 H NMR spectra are referenced to tetramethylsilane as an internal standard or the residual solvent signal of the respective solvent: CDCl 3 : δ = 7.26 ppm, CD 2 Cl 2 : δ = 5.32 ppm, and DMSO-d 6 : δ = 2.50 ppm. 13 C NMR spectra are referenced to the following signals: CDCl 3 : δ = 77.16 ppm, CD 2 Cl 2 : δ = 54.00 ppm, and DMSO-d 6 : δ = 39.52 ppm. The following abbreviations for multiplicities were used: singlet (s), broad singlet (br), doublet (d), triplet (t), quartet (q), multiplet (m), and combinations thereof, i.e., doublet of doublets (dd).…”

“…Column chromatography (silica gel, cyclohexane/DCM: 1/0 to 1/1) afforded 2 (1.45 g, 93%) as a yellow crystalline solid. R f = 0.83 (cyclohexane/EtOAc: 4/1); 1 H NMR (500 MHz, CDCl 3 ) δ = 7.30−7.22 (m, 1H), 7.20 (dd, J = 7.6, 1.7 Hz, 1H), 6.59 (dd, J = 8.2, 1.2 Hz, 1H), 6.56−6.51 (m, 1H), 4.90 (bs, 1H), 2.79 (s, 3H); 13 5.47 mg, 28.7 μmol, 2 mol%). The flask was evacuated and backfilled with argon, and degassed anhydrous toluene (30 mL) was added.…”

“…Column chromatography (silica gel, cyclohexane/CH 2 Cl 2 : 1/0 to 0/1) afforded 4 (343 mg, 71%) as a purple-red solid. R f = 0.46 (cyclohexane/EtOAc: 4/1); 1 H NMR (500 MHz, CDCl 3 ) δ = 8.65 (s, 2H), 8.21−8.09 (m, 2H), 7.83−7.73 (m, 2H), 7.10 (ddd, J = 7.8, 7.8, 1.3 Hz, 1H), 6.95 (dd, J = 7.6, 1.2 Hz, 1H), 6.74 (ddd, J = 7.6, 7.5, 1.1 Hz, 1H), 6.47 (dd, J = 8.0, 1.0 Hz, 1H), 2.83 (s, 3H); 13 [1,3]dithiole-2,1′-indene]−2′,3′-dione (8). A flamedried flask was charged with benzene-1,2-dithiol (5, 250 mg, 1.76 mmol, 1.0 equiv), 2,2-dihydroxy-1H-indene-1,3(2H)-dione (6, 344 mg, 1.93 mmol, 1.1 equiv), and p-TsOH•H 2 O (20.1 mg, 105 μmol, 6 mol%).…”

“…Analytical data for 7: R f = 0.22 (cyclohexane/EtOAc: 9/1); 1H-Cyclopenta[b]naphthalene-1,3(2H)-dione (13). Naphtho[2,3c]furan-1,3-dione (11, 15.1 g, 76.2 mmol, 1.0 equiv) was added to a solution of degassed anhydrous NEt 3 (60 mL) and degassed Ac 2 O (80 mL).…”

“…In the spiro-DA-compounds presented herein, 1,3-indandione and derivatives thereof were used as acceptor units (Figure , right). These have been incorporated in the past by the groups of Schönberg, − Maslak, − and Gleiter, and by us . We recently reported on the syntheses and optical properties of spiroconjugated dyes, which contained 1,3-indandione-based acceptors with aromatic methylated diamines as donors .…”