Vapochromic Platinum(II) Complexes: Crystal Engineering toward Intelligent Sensing Devices

Abstract

Abstract Vapochromic materials that show reversible color change driven by vapor adsorption/desorption have drawn significant attention because of their potential applications in chemical sensors and chemical‐switching modules. Among the vapochromic coordination complexes reported so far, a series of square‐planar Pt II complexes has been studied and represents one of the most promising systems for practical chemical sensors. For such systems, the color of the complexes strongly depends not only on the ligand‐field splitting, but also on the intermolecular distance between the Pt II ions. This microreview presents recent results of vapochromic complexes centered on one‐dimensionally stacked Pt II systems from the viewpoint of the origin of their vapochromic behavior. The design of vapochromic materials has been facilitated because several useful chromophores, including metallophilic interaction between Pt II ions, have been developed. However, it is still challenging to realize a specifically sensitive and selective response to targeted vapors. This review focuses on strategies to achieve assembled Pt II complexes with selective vapochromic responses.