Luminescence color change of a platinum(II) complex solid upon mechanical grinding.
The mechanochemical behavior of Pt(5dpb)Cl (5dpbH = 1,3-di(5-methyl-2-pyridyl)benzene) was investigated in terms of solid-state luminescence. The yellow luminescence of the crystalline complex changed to orange when grinding into fine powder on a glass substrate with a spatula. A broad emission band, which was not detected for the crystal, was observed at around 670 nm for the powder. The powder X-ray diffraction (XRD) pattern was the same as that calculated from X-ray crystallographic data of the single crystal. A broad band appeared within 100 ns after laser excitation accompanied by quenching of the s(pi,pi*) emission of Pt(5dpb)Cl, which was then weakened with decreasing temperature and disappeared below 120 K. The phenomenon was very similar to the excimer formation observed in solution. A related complex, Pt(dpb)Cl (dpbH = 1,3-di(2-pyridyl)benzene), also exhibited luminescent mechanochromism. However, the broad emission that appeared upon grinding still remained at 77 K, and XRD showed that the ground sample of Pt(dpb)Cl was amorphous.
Department of Chemistry Graduate School of Integrated Sciences, Yokohama City University, 22-2 Seto, Yokohama, 236-0027, Japan.
Taichi
T
Abe
Toru
T
Itakura
Noriaki
N
Ikeda
Kazuteru
K
Shinozaki