The photophysics of the 2,6 dialkoxy anthracenes: Evidence for excited state side-chain conformational relaxation

Synthesis and Photophysical Properties of 9,10-Disubstituted Anthracenes

“…On the other hand, the spectra of C and D are quite different from that of the unsubstituted DPA and are very similar to each other, with a large a bathochromic shift resulting in a main peak at 485 and 490 nm, respectively, and a smaller one around 520 nm. Similar to the case of absorption, these characteristics resemble the results reported in 2,6 substituted anthracene derivatives [9], thus confirming that the carbon-carbon triple bonds effectively alter the electronic states of the anthracene core, also by improving the conjugation along the 9,10-phenyl axis. Moreover, when C and D are excited at either the absorption group centred at 310 and the one at 450 nm, respectively, the same PL spectra around 500 nm are observed indicating that the carbon-carbon triple bonds still allow an effective intramolecular relaxation.…”

“…Conversely, quite noticeable effects are produced by the substitution of the carbon-carbon triple bonds for the single bonds linking the two 9,10-phenyls, which is performed in C and D. The higher-energy peak exhibits a bathochromic shift from 260 nm to approximately 275 nm and, more significantly, the lower-energy progression is apparently split in two groups, centred at 310 and 450 nm, respectively, which exhibit a fourfold increase of the molar absorptivity in comparison with DPA, with values as high as ε ≅ 4 × 10 4 M −1 •cm −1 . A similar splitting, with the arising of two well defined progressions centred at 325 and 390 nm, was observed in 2,6 substituted anthracene derivatives [9] and attributed to a mixing of the two low-lying excited states L a and L b of polyacenes, with the reorientation of the dipole moments and remodulation of the respective oscillator strength. Moreover, the spectra of C and D display a certain dependence on the type and positions of the 9,10-phenyls substituents, with D exhibiting an appreciably higher bathochromic shift.…”

“…Synthesis and investigations have especially been aimed to achieve efficient, pure and stable emission in the blue side of the spectrum as well as to accomplish tunability towards longer wavelengths and good solubility for spin-coating processing. Specifically, even though recent studies have addressed the 2,6-substituted anthracenes [9], which are less prone to face-to-face packing (π-π stacking) and consequent decrease of emission efficiency, the greatest interest has been risen by the 9,10-substituted anthracenes and especially by 9,10-disubstituted diphenylanthracene (DPA) derivatives [6] [7] [14]- [20], basing on the 95% quantum yield of DPA itself and on the great chance of molecular engineering offered by its molecular structure. Within this framework, we have synthesized four 9,10-disubstituted diphenylanthracene derivatives with specific modifications of the model backbone, involving both 9,10 para substituents at the phenyl rings and the substitution with carbon-carbon triple bonds.…”

Photoinduced processes in macrocyclic isoalloxazine–anthracene systems

“…Anthracene moieties were chosen in this occasion due to its robust photophysical properties and because of their ability to donate electrons. In particular, spectroscopic and photophysical properties of dialkoxyanthracenes [35,36] are very sensitive to various parameters (solvent, concentration, substitution, quenchers) and they have been used as components of photoswitches, conjugated polymers and supramolecular assemblies [37]. They can act as very powerful probes able to reveal weak molecular interactions such as p-p stacking, donor-acceptor, etc.…”

Interfacial Self-Assembly and Characterization of Chiral Coordination Polymer Multilayers with Bidentate Ligands of Hydroquinine Anthraquinone-1,4-diyl Diether as Linkers

“…34 The anthraquinone derivatives also give off strong luminescent emissions. 35 They can further act as lightharvesting units to absorb light energy and then transfer it to some metal ions like Eu 3+ and Tb 3+ as luminophores, sensors, and organic light-emitting diodes. 36 Since the chiral ligands of (DHQ) 2 AQN and (DHQD) 2 AQN contain both quinine and anthraquinone substituents, they are expected to show interesting luminescent behaviors in the LB films.…”