Pressure-Induced Sequential Orbital Reorientation in a Magnetic Framework Material


  • Work performed at Argonne National Laboratory and use of the Advanced Photon Source were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Part of the pressure cell preparation used the GSECARS facility (Sector 13), Advanced Photon Source, Argonne National Laboratory. GSECARS is supported by the NSF-Earth Sciences (EAR-0622171) and DOE-Geosciences (DE-FG02-94ER14466). Work at EWU was partially supported by the National Science Foundation under Grant No. DMR-1005825.


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Pressure-dependent isomerization: Pressure has been applied to manipulate the structure–property relationship of the copper(II)-based coordination network CuF2(H2O)2(pyz) (pyz=pyrazine). The elongated Jahn–Teller axis was found to switch sequentially from the N[BOND]Cu[BOND]N (<0.9 GPa), to the O[BOND]Cu[BOND]O (0.9–3.1 GPa), to the F[BOND]Cu[BOND]F bonds (>3.1 GPa; see picture). This orbital reordering leads to a drastic change in the magnetic properties, whereby the magnetic structure changes from two-dimensional to one-dimensional above 0.9 GPa.