Insulator to metal transition and electronic spectra of bis(1,2-benzoquinonedioximato)platinum(II), Pt(bqd)2 at high pressure

Abstract High quality single crystals of one-dimensional bis(1,2-benzoquinonedioximato)platinum(II), Pt(bqd) 2 were prepared using the diffusion method. Polarized reflectance spectra of the single crystal of Pt(bqd) 2 have been measured at low temperatures under ambient pressure. We found four peaks at around 8000, 6700, 5400 and 4000 cm −1 in the wide band assigned from the 5d z 2 to 6p z transition in platinum. As these peaks are very sensitive to temperature, the fine structures may arise from the intramolecular vibration. The absorption spectra of the oriented film of Pt(bqd) 2 have been studied at high pressures. The absorption intensity of the four peaks remarkably increases with increasing pressure. These peaks rapidly shift to the lower energy side up to 0.66 GPa and almost disappear at around 0.88 GPa. This optical behavior is due to the insulator to metal transition observed at around 0.8 GPa.