TY - JOUR

T1 - Alkyl-substituted bis(4-((9H-fluoren-9-ylidene)methyl)phenyl)thiophenes

T2 - weakening of intermolecular interactions and additive-assisted crystallization

AU - Sonina, Alina A.

AU - Becker, Christina S.

AU - Kuimov, Anatoly D.

AU - Shundrina, Inna K.

AU - Komarov, Vladislav Yu

AU - Kazantsev, Maxim S.

N1 - Funding Information: This work was supported by the State Assignment of Ministry of Science and Higher Education of Russian Federation, project #0238-2019-0004. The authors thank the XRD Facility of NIIC SB RAS for the data collection. Powder diffraction experiments were carried out at the Research and Education Centre of the Novosibirsk State University REC-008. The assistance of Dr. Evgeny Losev is gratefully acknowledged. The authors acknowledge the Multi-Access Chemical Service Center SB RAS for the spectral and analytical measurements. Publisher Copyright: © The Royal Society of Chemistry 2021. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/4/14

Y1 - 2021/4/14

N2 - Aggregation-induced emission (AIE) materials find their applications in organic optoelectronics, bio-imaging and sensors. In this work, we introduced alkyl substituents in AIE-active bis(4-((9H-fluoren-9-ylidene)methyl)phenyl)thiophene and elucidated their effect on the molecular and crystal structures, crystallization and optical properties of materials. Ethyl-containing (C2-BFMPT) and octyl-containing (C8-BFMPT) 2,5-bis(4-((2,7-dialkyl-9H-fluoren-9-ylidene)methyl)phenyl)thiophenes were synthesized in 4 steps. The introduction of alkyl groups weakened intermolecular interactions, decreased the crystal quality, melting point, and density, and increased the solubility of materials. Octyl-containing derivative was demonstrated to generate two crystal forms obtained by the native (form I) and additive-assisted (form II) crystallizations. The latter appeared to have a better crystal quality. C-H⋯π interactions and an extensive positional disorder were revealed for both derivatives. In C8-BFMPT crystals (form II) only a half of molecular backbones were well localized due to multiple intermolecular C-H⋯π interactions, whereas another half demonstrated a high positional disorder. The AIE effect with a negligible photoluminescence (PL) quantum yield (QY) in solution and a PL QY of 5% for C2-BFMPT and 2% for C8-BFMPT (form II) crystals was demonstrated. The cooling of the C8-BFMPT form II resulted in 10-fold increase of PL QY. The introduction of alkyl-substituents and additive-assisted crystallization are highlighted as powerful tools for the control of crystal packing, morphology, polymorphism and the optical performance of AIE-materials.

AB - Aggregation-induced emission (AIE) materials find their applications in organic optoelectronics, bio-imaging and sensors. In this work, we introduced alkyl substituents in AIE-active bis(4-((9H-fluoren-9-ylidene)methyl)phenyl)thiophene and elucidated their effect on the molecular and crystal structures, crystallization and optical properties of materials. Ethyl-containing (C2-BFMPT) and octyl-containing (C8-BFMPT) 2,5-bis(4-((2,7-dialkyl-9H-fluoren-9-ylidene)methyl)phenyl)thiophenes were synthesized in 4 steps. The introduction of alkyl groups weakened intermolecular interactions, decreased the crystal quality, melting point, and density, and increased the solubility of materials. Octyl-containing derivative was demonstrated to generate two crystal forms obtained by the native (form I) and additive-assisted (form II) crystallizations. The latter appeared to have a better crystal quality. C-H⋯π interactions and an extensive positional disorder were revealed for both derivatives. In C8-BFMPT crystals (form II) only a half of molecular backbones were well localized due to multiple intermolecular C-H⋯π interactions, whereas another half demonstrated a high positional disorder. The AIE effect with a negligible photoluminescence (PL) quantum yield (QY) in solution and a PL QY of 5% for C2-BFMPT and 2% for C8-BFMPT (form II) crystals was demonstrated. The cooling of the C8-BFMPT form II resulted in 10-fold increase of PL QY. The introduction of alkyl-substituents and additive-assisted crystallization are highlighted as powerful tools for the control of crystal packing, morphology, polymorphism and the optical performance of AIE-materials.

UR - http://www.scopus.com/inward/record.url?scp=85104094700&partnerID=8YFLogxK

U2 - 10.1039/d0ce01794a

DO - 10.1039/d0ce01794a

M3 - Article

AN - SCOPUS:85104094700

VL - 23

SP - 2654

EP - 2664

JO - CrystEngComm

JF - CrystEngComm

SN - 1466-8033

IS - 14

ER -