Using sulfur bridge oxidation to control electronic coupling and photochemistry in covalent anthracene dimers

Abstract

For anthracene dimers bridged by a sulfur atom, modulating the sulfur oxidation state profoundly affects excited state behavior. The SO2-bridge supports long-lived states and photodimerization, while the S-bridge undergoes intersystem crossing.

Controlling ultralong room temperature phosphorescence in organic compounds with sulfur oxidation state

“…S14 and S15 †). 25,26 The increase in interchromophoric interaction and CT character of excited states with the oxidation state of the linker is consistent with our previous ndings 23 and computational studies showing a similar decrease of the electronic screening effect of sulfur lone pairs from S, to SO and SO 2 -bridged dimers. 24 Before carrying out solid-state photophysical measurements, powder X-ray diffraction (pXRD) patterns of CBZ-S and CBZ-SO were collected in order to determine the crystallinity and phase of the bulk samples (Fig.…”

“…We have also demonstrated that the oxidation state at the sulfur bridge of conjugated homodimers, such as naphthalene or anthracene, controls their photochemistry by promoting photodimerization or enhancing the nonradiative decay through a conical intersection. 25,26 The concept of tuning the electronics of a species by varying the sulfur oxidation state has since been applied to various molecular systems including oligomers, polymers and metal complexes. [27][28][29][30][31][32] In the bridged terthiophene compounds, the bridging sulfur lone pairs (n(S)) are low in energy compared to the p HOMO of terthiophene, and thus do not participate signicantly in the low-lying excited states.…”

“…However, for higher bandgap chromophores like naphthalene and anthracene, the n(S) orbitals are able to mix with the chromophore HOMOs. 25,26 Given the involvement of (n, p*) excited states in RTP, it would be intriguing to vary the n(S) component in sulfur-bridged chromophores using oxidation state, to control phosphorescence. There are two questions that are interesting to consider: (1) can the n(S) lone pairs inuence intersystem crossing in phosphorescent organic compounds directly by increasing the singlet and/or triplet (n, p*) character or indirectly via the lone pair screening effect and creation of CT states?, and (2) since sulfone groups have been frequently used to enhance (n, p*) character in RTP compounds, 13,14,16,[19][20][21] how do the oxygen lone pair orbitals (n(O)) in the SO 2 group affect the (n, p*) transition compared to the n(S) orbitals in sulde?…”

Efficient singlet fission in nanoparticles of amphipathic anthracene–tetracene dyad with broadband light harvesting ability

“…These two PIA bands are attributed to the absorption of the singlet (S 1 ) state of DPA based on the previous report. 50,51 With time delay, these two S 1 absorption bands showed an increase within the first ∼20 ps, as revealed by single-wavelength dynamics probed at ∼375 and ∼580 nm (Fig. S4, ESI†), which should be caused by vibrational cooling and rotation of the two phenyl rings at 9,10-position of DPA in the S 1 state.…”

Dynamic anti-counterfeiting security features using multicolor dianthryl sulfoxides

“…This concept of temporal uorescence evolution is based on photochemical behavior found in sulfur-bridged dianthracenes that is dependent on the oxidation state of the sulfur bridge. 55,56 The weakly emissive 9,9 0 -dianthryl sulfoxide (1a) eliminates the SO bridge upon photoirradiation to form the strongly blue emissive molecule 9,9 0 -bianthracene (1b) ( Fig. 1) either in solution, or in polymer host matrices with glass transition temperatures (T g ) below room temperature, such as poly(butylmethacrylate).…”