TY - JOUR

T1 - BN-Substitution in Dithienylpyrenes Prevents Excimer Formation in Solution and in the Solid State

AU - Appiarius, Yannik

AU - Gliese, Philipp J.

AU - Segler, Stephan A.W.

AU - Rusch, Pascal

AU - Zhang, Jiangbin

AU - Gates, Paul J.

AU - Pal, Rumpa

AU - Malaspina, Lorraine A.

AU - Sugimoto, Kunihisa

AU - Neudecker, Tim

AU - Bigall, Nadja C.

AU - Grabowsky, Simon

AU - Bakulin, Artem A.

AU - Staubitz, Anne

N1 - Funding Information: Y.A., P.J. Gliese, S.A.W.S., A.S., R.P., L.A.M., and S.G. thank the German Research Foundation (DFG) for funding as part of the Emmy-Noether Program (STA 1195/2-1 and GR 4451/1-1). This research has been supported by the Institutional Strategy of the University of Bremen, funded by the German Excellence Initiative. N.C.B. and P.R. thank the DFG for partial funding under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453) and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 714429). A.A.B. is a Royal Society University Research Fellow. J.Z. thanks the China Scholarship Council for the financial support for his Ph.D. studies and the Science and Technology Innovation Program of Hunan Province (2021RC3083). The synchrotron measurements were supported by SPring-8 under proposal no. 2016B1204.

PY - 2022/3/10

Y1 - 2022/3/10

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85125925133&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.1c08812

DO - 10.1021/acs.jpcc.1c08812

M3 - Article

AN - SCOPUS:85125925133

VL - 126

SP - 4563

EP - 4576

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 9

ER -