BN-Substitution in Dithienylpyrenes Prevents Excimer Formation in Solution and in the Solid State.

Appiarius, Yannik; Gliese, Philipp J; Segler, Stephan A W; Rusch, Pascal; Zhang, Jiangbin; Gates, Paul J; Pal, Rumpa; Malaspina, Lorraine A; Sugimoto, Kunihisa; Neudecker, Tim; Bigall, Nadja C; Grabowsky, Simon; Bakulin, Artem A; Staubitz, Anne (2022). BN-Substitution in Dithienylpyrenes Prevents Excimer Formation in Solution and in the Solid State. Journal of physical chemistry. C, 126(9), pp. 4563-4576. American Chemical Society 10.1021/acs.jpcc.1c08812

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Boron-nitrogen substitutions in polycyclic aromatic hydrocarbons (PAHs) have a strong impact on the optical properties of the molecules due to a significantly more heterogeneous electron distribution. However, besides these single-molecule properties, the observed optical properties of PAHs critically depend on the degree of intermolecular interactions such as π-π-stacking, dipolar interactions, or the formation of dimers in the excited state. Pyrene is the most prominent example showing the latter as it exhibits a broadened and strongly bathochromically shifted emission band at high concentrations in solution compared to the respective monomers. In the solid state, the impact of intermolecular interactions is even higher as it determines the crystal packing crucially. In this work, a thiophene-flanked BN-pyrene (BNP) was synthesized and compared with its all-carbon analogue (CCP) in solution and in the solid state by means of crystallography, NMR spectroscopy, UV-vis spectroscopy, and photoluminescence (PL) spectroscopy. In solution, PL spectroscopy revealed the solvent-dependent presence of excimers of CCP at high concentrations. In contrast, no excimers were found in BNP. Clear differences were also observed in the single-crystal packing motifs. While CCP revealed overlapped pyrene planes with centroid distances in the range of classical π-stacking interactions, the BNP scaffolds were displaced and significantly more spatially separated.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Malaspina, Lorraine and Grabowsky, Simon

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

1932-7447

Publisher:

American Chemical Society

Language:

English

Submitter:

Pubmed Import

Date Deposited:

21 Mar 2022 09:46

Last Modified:

21 Mar 2022 09:52

Publisher DOI:

10.1021/acs.jpcc.1c08812

PubMed ID:

35299818

BORIS DOI:

10.48350/167657

URI:

https://boris.unibe.ch/id/eprint/167657

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