How the Length of Through-Space Conjugation Influences the Clusteroluminescence of Oligo(Phenylene Methylene)s

Lei Wang; Zuping Xiong; Jing Zhi Sun; Feihe Huang; Haoke Zhang; Ben Zhong Tang

doi:10.1002/anie.202318245

How the Length of Through-Space Conjugation Influences the Clusteroluminescence of Oligo(Phenylene Methylene)s

Angew Chem Int Ed Engl. 2024 Feb 19;63(8):e202318245. doi: 10.1002/anie.202318245. Epub 2024 Jan 16.

Authors

Lei Wang^{1

2}, Zuping Xiong^{1

2

3}, Jing Zhi Sun^{1

3}, Feihe Huang^{2

4}, Haoke Zhang^{1

2

3}, Ben Zhong Tang^{1

5}

Affiliations

¹ MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310058, China.
² Zhejiang-Israel Joint Laboratory of Self-Assembling Functional Materials, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, China.
³ Centre of Healthcare Materials, Shaoxing Institute, Zhejiang University, Shaoxing, 312000, China.
⁴ Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China.
⁵ School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), Guangdong, 518172, China.

PMID: 38165147
DOI: 10.1002/anie.202318245

Abstract

The length and mode of conjugation directly affect the molecular electronic structure, which has been extensively studied in through-bond conjugation (TBC) systems. Corresponding research greatly promotes the development of TBC-based luminophores. However, how the length and mode of through-space conjugation (TSC), one kind of weak interaction, influence the photophysical properties of non-conjugated luminophores remains a relatively unexplored field. Here, we unveil a non-linear relationship between TSC length and emission characteristics in non-conjugated systems, in contrast to the reported proportional correlation in TBC systems. More specifically, oligo(phenylene methylene)s (OPM[4]-OPM[7]) exhibit stronger TSC and prominent blue clusteroluminescence (CL) (≈440 nm) compared to shorter counterparts (OPM[2] and OPM[3]). OPM[6] demonstrates the highest solid-state quantum yield (40 %), emphasizing the importance of balancing flexibility and rigidity. Further theoretical calculations confirmed that CL of these oligo(phenylene methylene)s was determined by stable TSC derived from the inner rigid Diphenylmethane (DPM) segments within the oligomers instead of the outer ones. This discovery challenges previous assumptions and adds a new dimension to the understanding of TSC-based luminophores in non-conjugated systems.

Keywords: Aggregation-Induced Emission; Clusteroluminescence; Oligo(Phenylene Methylene)s; Through-Space Conjugation.

Abstract

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