Versatile Room-Temperature-Phosphorescent Materials Prepared from N-Substituted Naphthalimides: Emission Enhancement and Chemical Conjugation

Xiaofeng Chen; Cheng Xu; Tao Wang; Cao Zhou; Jiajun Du; Zhongping Wang; Hangxun Xu; Tongqing Xie; Guoqiang Bi; Jun Jiang; Xuepeng Zhang; James N Demas; Carl O Trindle; Yi Luo; Guoqing Zhang

doi:10.1002/anie.201601252

Versatile Room-Temperature-Phosphorescent Materials Prepared from N-Substituted Naphthalimides: Emission Enhancement and Chemical Conjugation

Angew Chem Int Ed Engl. 2016 Aug 16;55(34):9872-6. doi: 10.1002/anie.201601252. Epub 2016 Jul 7.

Authors

Xiaofeng Chen^{1

2}, Cheng Xu¹, Tao Wang¹, Cao Zhou¹, Jiajun Du², Zhongping Wang³, Hangxun Xu², Tongqing Xie¹, Guoqiang Bi¹, Jun Jiang¹, Xuepeng Zhang⁴, James N Demas⁵, Carl O Trindle⁵, Yi Luo¹, Guoqing Zhang⁶

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, P.R. China.
² Department of Polymer Science and Engineering, University of Science and Technology of China, 230026, Hefei, P.R. China.
³ Physics Experiment Teaching Center, University of Science and Technology of China, 230026, Hefei, P.R. China.
⁴ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, P.R. China. zhangxp@mail.ustc.edu.cn.
⁵ Department of Chemistry, University of Virginia, Charlottesville, VA, 22903, USA.
⁶ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, P.R. China. gzhang@ustc.edu.cn.

PMID: 27385550
DOI: 10.1002/anie.201601252

Abstract

Purely organic materials with room-temperature phosphorescence (RTP) are currently under intense investigation because of their potential applications in sensing, imaging, and displaying. Inspired by certain organometallic systems, where ligand-localized phosphorescence ((3) π-π*) is mediated by ligand-to-metal or metal-to-ligand charge transfer (CT) states, we now show that donor-to-acceptor CT states from the same organic molecule can also mediate π-localized RTP. In the model system of N-substituted naphthalimides (NNIs), the relatively large energy gap between the NNI-localized (1) π-π* and (3) π-π* states of the aromatic ring can be bridged by intramolecular CT states when the NNI is chemically modified with an electron donor. These NNI-based RTP materials can be easily conjugated to both synthetic and natural macromolecules, which can be used for RTP microscopy.

Keywords: charge transfer; fluorescence; naphthalimides; organic dyes; phosphorescence.

Publication types

Research Support, Non-U.S. Gov't