Pressure-sensitive absorption spectra of thin films of bis(diphenylglyoximato)platinum(II), Pt(dpg)2: potential application as an indicator of pressure

Abstract

The optical properties of thin films of Pt(dpg)₂ have been studied at high pressures. Two absorption bands of the complex in the visible region shifted sharply to longer wavelengths with increasing pressure. The rates of the red shift with pressure were ca.–1900 cm^–1 GPa^–1 for the metal-to-ligand charge-transfer(M–L) band and –3000 cm^–1 GPa^–1 for the 5d-6p band. These values are the largest in the known one-dimensional d⁸ metal complexes. The colours of the thin films in the diamond-anvil pressure cell were observed visullay at various pressures. The colours of Pt(dpg)₂ turned from red–brown at atmospheric pressure to brown at 0.27 GPa, green at 0.69 GPa, to yellow–green at 1.24 GPa and yellow at 1.92 GPa. This material can be utilized as an indicator of pressure over a GPa range 0–2.