Modular electron donor group tuning of frontier energy levels in diarylaminofluorenone push–pull molecules

Abstract

Push-pull organic molecules composed of electron donor diarylamines at the 2- and 2,7-positions of fluorenone exhibit intramolecular charge-transfer behaviour in static absorption and emission spectra. Electrochemical and spectral data combined in a modular electronic analysis model show how the donor HOMO and acceptor LUMO act as major determinants of the frontier molecular orbital energy levels.

A New Photocage Derived from Fluorene

“…The crude product was purified by column chromatography (SiO 2 , cyclohexane/ethyl acetate 19:1 to 9:1 to 3:1) to give the product as a dark foam (200 mg, 22 %). 1 H NMR (400 MHz, [D 6 ]DMSO): δ =7.60–7.57 (m, 1 H), 7.56–7.48 (m, 3 H), 7.25–7.20 (m, 1 H), 7.14–7.07 (m, 4 H), 6.99–6.94 (m, 4 H), 6.90–6.83 (m, 2 H), 3.76 ppm (s, 6 H); NMR data were in agreement with that reported in the literature …”

“…Examples of synthetic procedures for selected key compounds are given in the following text. Synthetic details for other compounds can be found in the Supporting Information …”

“…Synthetic details for other compounds can be found in the Supporting Information. [26,[52][53][54][55][56][57] Generalp rocedure A-Steglich-typeesterification:Synthesis of P2 5-Diethylamino-2-iodobenzyl alcohol (10.0 g, 32.8 mmol, 1.0 equiv) was dissolved in CH 2 Cl 2 (100 mL). EDC-HCl (10.0 g, 52.3 mmol, 1.6 equiv), DIPEA (5.07 g, 39.3 mmol, 1.2 equiv), DMAP (0.4 g, 3.3 mmol, 0.1 equiv), and N-(tert-butoxycarbonyl)-l-glutamic acid 1tert-butyl ester (15.0 g, 49.5 mmol, 1.5 equiv) were added to the solution.…”

“…1 HNMR (400 MHz, [D 6 ]DMSO): d = 7.60-7.57 (m, 1H), 7.56-7.48 (m, 3H), 7.25-7.20 (m, 1H), 7.14-7.07 (m, 4H), 6.99-6.94 (m, 4H), 6.90-6.83 (m, 2H), 3.76 ppm (s, 6H); NMR data were in agreement with that reported in the literature. [52] General procedure G-reductiono fcarbonyl group with NaBH 4 :S ynthesis of 13 a Compound 12 a (200 mg, 0.49 mmol, 1equiv) was dissolved in a 1:1m ixture of THF/EtOH (5 mL) and cooled on an ice bath. Then NaBH 4 (28 mg, 0.74 mmol, 1.5 equiv) was added and the cooling bath was removed.…”

Radical cations from diarylamino-substituted fluorenones

“…All of the monoamines show reversible to quasi-reversible behavior indicating good stability of the radical cations, especially when para-donor substituents that block dimerization are present (DAAFO, DAAFOPV). Hybrid density functional theory B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) computations 9,10 for the neutral amines give good agreement of computed HOMO energy levels with observed first oxidation potentials converted8,11 into HOMO energies (despite taking no computational account of solvent or counterion effects).…”