Development of Bright Luminescent Platinum(II) Complexes Capable of Responding to Various External Stimuli

Stimuli-responsive luminescent materials, so-called “luminescent chromic materials,” have attracted increasing interest due to their wide range of applications, including optoelectronic devices, luminescent sensors, and probes. In particular, self-assembled square-planar platinum(II) complexes have occupied a unique position because of their intense and stimuli-responsive luminescent properties arising from the metallophilic interactions. However, the design strategies for the chromic platinum(II) complexes remain a significant challenge. The author has recently focused on the development of this molecular design strategy for the stimuli-responsive luminescent platinum(II) complexes. In this account, the design principle of strongly luminescent platinum(II) complexes is first introduced, followed by the principle of luminescence color change due to metallophilic interactions. Finally, our concept of designing luminescent chromic platinum(II) complexes with counter cations is presented, as a means to more conveniently and strategically design metastable and transient states.