Pressure-induced insulator-to-metal-to-insulator: transitions in once-dimensional bis(dimethylglyoximato)platinum(II), Pt(dmg)(2)

Citation
K. Takeda et al., Pressure-induced insulator-to-metal-to-insulator: transitions in once-dimensional bis(dimethylglyoximato)platinum(II), Pt(dmg)(2), CHEM MATER, 12(4), 2000, pp. 912-916
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
CHEMISTRY OF MATERIALS
ISSN journal
0897-4756 → ACNP
Volume
12
Issue
4
Year of publication
2000
Pages
912 - 916
Database
ISI
SICI code
0897-4756(200004)12:4<912:PITIO>2.0.ZU;2-8
Abstract
Electrical resistivities, absorption spectra, and X-ray diffraction of one- dimensional bis(dimethylglyoximato)platinum(IP), Pt(dmg)(2), have been stud ied in detail at high pressures, The resistivity drastically decreases with increasing pressure and reaches the minimum at around 6.5 GPa and then slo wly increases with increasing pressure above this pressure. The pressure-in duced insulator-to-metal-to-insulator (IMI) transitions in the complex have been found at around 5 and 6.5 GPa, respectively. The absorption spectra i n the 25000-3000 cm(-1) region were measured with a diamond-anvil cell up t o 10 GPa at room temperature. The absorption band based on the 5d(z2)-6p(z) transition at around 660 nm shifts remarkably to longer wavelengths with a rate of the pressure shift of - 2300 cm(-1)/GPa, The optical energy gap be tween 5d(z2) and 6p(z) bands becomes zero at around 5 GPa, The absorption s pectra of Pt(dmg)(2) markedly change at around the pressures which show the IMI transitions. By use of synchrotron radiation, the powder X-ray diffrac tion of Pt(dmg)(2) has been studied up to 10 GPa at room temperature. The l attice constants monotonically decrease with increasing pressure. The Pt-Pt distance within the chain, half of the c-axis, decreases continuously up t o 10 GPa, The intermolecular interaction between the adjacent molecules inc reases remarkably with decreasing the a- and b-axes, However, the crystal s tructure does not change up to 10 GPa, The pressure-induced IMI transitions and the resistivity minimum arise from the change of the electronic states of Pt(dmg)(2) at high pressures.