The international joint research group led by Professor Takumi KONNO (Graduate School of Science, Osaka University) discovered an extremely emissive gold(I) compound, which shows reversible, two-step emission color change in response to heating and grinding (Figure 1), and elucidated the conversion mechanism. In this compound, each of two gold(I) ions adopts a ‘3-coordinated trigonal-planar’ geometry, rather than a usual ‘2-coordinated linear’ geometry. Based on this finding, gold(I) chromic compounds, the emission colors of which are made to vary in respond to external stimuli, will be used to various applications, such as luminous paints and chemical sensors.

Figure 1　Reversible conversion of “Green emitting complex”, “yellow emitting complex”, and “blue emitting complex” by heating and by mechanical force.

(Link) http://resou.osaka-u.ac.jp/en/research/2016/20160527_1