Research Area
Fluorescent Materials
C4N4 fluorophores are small, modular, and surprisingly expressive molecules for turning structure into light.
Overview
Our C4N4 fluorophores are based on diaminopyrimidine units made from four carbon and four nitrogen atoms. They can be assembled in a modular, one-step fashion from readily available starting materials, which makes them an unusually accessible platform for fluorescence design.
The molecules typically show large Stokes shifts and solid-state emission. That combination is useful for imaging, sensing, and materials-oriented applications, but it is also a good playground for asking a more basic question: how does a simple heteroaromatic framework decide what color, brightness, and environment response it will have?
Because the framework is easy to modify, we can tune the periphery, introduce higher-order structures, and explore guest sensing and circularly polarized luminescence. In a seminar, this is the part where the molecule starts looking less like a dye and more like a small programmable device.
What we are asking
Accessible fluorophores
Can a very short synthesis still give a platform rich enough for sophisticated photophysics?
Structure-light logic
Which molecular features control emission in solution, solids, and crowded environments?
Imaging and sensing
How far can modular C4N4 design be pushed toward probes and responsive materials?
Visual Notes
Representative Publications
- A Fluorogenic C4N4 Probe for Azide-Based Labelling
Hidetoshi Noda, Yasuko Asada, Masakatsu Shibasaki,* and Naoya Kumagai*
Org. Biomol. Chem. 2019, 17, 1813-1816. - A C4N4 Diaminopyrimidine Fluorophore
Hidetoshi Noda, Yasuko Asada, Tatsuro Maruyama, Naoki Takizawa, Nobuo N. Noda, Masakatsu Shibasaki,* and Naoya Kumagai*
Chem. Eur. J. 2019, 25, 4299-4304. - Strategic Synthesis of Asymmetrically Substituted C4N4 Fluorophores
Wei Xu, Miki Kohei, Masakatsu Shibasaki,* and Naoya Kumagai*
Synthesis 2021, 53, 3355-3360. - Revisiting C4N4 Fluorophore: Theoretical Elucidation of the Origin of Fluorescent Properties of 2,5-Diaminopyrimidines and Strategic Applications to Pd Detection
Miki Kohei, Itsuki Kondo, Go Kawamura, Yu Harabuchi, Satoshi Maeda, and Naoya Kumagai*
Chem. Eur. J. in press.