Guest-Dependent Spin Crossover in a Nanoporous Molecular Framework Material
Gregory J. Halder,1
Cameron J. Kepert,1*
Boujemaa Moubaraki,2
Keith S. Murray,2
John D. Cashion3
The nanoporous metal-organic framework
Fe2(azpy)4(NCS)4·(guest) (azpy is
trans-4,4'-azopyridine) displays reversible uptake and
release of guest molecules and contains electronic switching centers
that are sensitive to the nature of the sorbed guests. The switching of
this material arises from the presence of iron(II) spin crossover
centers within the framework lattice, the sorbed phases undergoing
"half-spin" crossovers, and the desorbed phase showing no switching
property. The interpenetrated framework structure displays a
considerable flexibility with guest uptake and release, causing
substantial changes in the local geometry of the iron(II) centers. The
generation of a host lattice that interacts with exchangeable guest
species in a switchable fashion has implications for the generation of
previously undeveloped advanced materials with applications in areas
such as molecular sensing.
1 School of Chemistry, University of Sydney,
Sydney, NSW 2006, Australia.
2 School of Chemistry,
Post Office Box 23,
3 School of Physics and
Materials Engineering, Post Office Box 27, Monash University,
Melbourne, VIC 3800, Australia.
*
To whom correspondence should be addressed. E-mail:
c.kepert{at}chem.usyd.edu.au
