title: Push-Pull Type Oligo(N-annulated perylene)quinodimethanes: Chain Length and Solvent-Dependent Ground States and Physical Properties.
abstract: Research on stable open-shell singlet diradicaloids recently became a hot topic because of their unique optical, electronic, and magnetic properties and promising applications in materials science. So far, most reported singlet diradicaloid molecules have a symmetric structure, while asymmetric diradicaloids with an additional contribution of a dipolar zwitterionic form to the ground state were rarely studied. In this Article, a series of new push-pull type oligo(N-annulated perylene)quinodimethanes were synthesized. Their chain length and solvent-dependent ground states and physical properties were systematically investigated by various experimental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device, Raman spectroscopy, and electrochemistry. It was found that with extension of the chain length, the diradical character increases while the contribution of the zwitterionic form to the ground state becomes smaller. Because of the intramolecular charge transfer character, the physical properties of this push-pull system showed solvent dependence. In addition, density functional theory calculations on the diradical character and Hirshfeld charge were conducted to understand the chain length and solvent dependence of both symmetric and asymmetric systems. Our studies provided a comprehensive understanding on the fundamental structure- and environment-property relationships in the new asymmetric diradicaloid systems.
authors.affiliation: †Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.|‡State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Zebing
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: §Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
authors.forename: Sangsu
authors.initials: S
authors.lastname: Lee
authors.affiliation: §Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
authors.forename: Minjung
authors.initials: M
authors.lastname: Son
authors.affiliation: ∥Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Fukuda
authors.affiliation: ⊥Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071 Málaga, Spain.
authors.forename: Paula Mayorga
authors.initials: PM
authors.lastname: Burrezo
authors.affiliation: #Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhu
authors.affiliation: †Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Qingbiao
authors.initials: Q
authors.lastname: Qi
authors.affiliation: #Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China.
authors.forename: Run-Wei
authors.initials: RW
authors.lastname: Li
authors.affiliation: ⊥Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071 Málaga, Spain.
authors.forename: Juan T López
authors.initials: JT
authors.lastname: Navarrete
authors.forename: Jun
authors.initials: J
authors.lastname: Ding
authors.affiliation: ⊥Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071 Málaga, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Casado
authors.affiliation: ∥Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nakano
authors.affiliation: §Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim
authors.affiliation: †Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Jishan
authors.initials: J
authors.lastname: Wu