Stable Iminium Singlet and Triplet Diradical(oid)s with Intense NIR‐II Absorptions
Abstract
Abstract This study presents the successful synthesis of a series of stable iminium diradical(oid)s. CNR1 + OTf − , CNR2 + OTf − , and CNR3 + OTf − can be readily prepared by treating their corresponding methoxy precursors with triflate acid. Remarkably, they all display excellent stability under light and ambient conditions. CNR1 + exhibits a closed shell electronic feature, whereas CNR2 + features an open shell singlet ground state. CNR3 + OTf − possess triplet ground electronic state, as evidenced by ESR and superconducting quantum interference device (SQUID) measurements. Through meticulous fitting of the SQUID data, a singlet‐triplet energy gaps (∆ E S‐T ) of +1.04 kcal mol −1 along with intermolecular antiferromagnetic interactions ( θ ) of ‐28 K were obtained. In comparison to CNR1 + , both the open shell CNR2 + and CNR3 + display distinctively red shifted long wavelength absorption bands that extend up to approximately 2400 nm. Such long wavelength absorption characteristics are quite scarce among organic materials. This research offers a novel approach for the design and synthesis of iminium diradical(oid)s, which feature tunable ground states and exhibit intense absorption in the second near infrared (NIR‐II) region, opening up new possibilities in the field of organic materials research.
Article Details
Authors (8)
Wen Ji
Ya Zou
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
Lu Guo
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
Weiwei Niu
Center of Single-Molecule Sciences, Institute of Modern Optics, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin 300350, China
Tianyu Jiao
Department of Chemistry National University of Singapore Singapore
Hoa Phan
School of Chemistry and Life Science Hanoi University of Science and Technology No. 1 Dai Co Viet Ha Ba Trung Hanoi Vietnam
Jishan Wu
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
Guangwu Li
Center of Single-Molecule Sciences, Institute of Modern Optics, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering