In-situ single
crystal x-ray diffraction studies of guest‑exchange in nanoporous
framework materials
Gregory J. Halder,a Cameron J. Kepert,a Boujemaa Moubaraki,b Keith S. Murray,b and John D. Cahsionc
aDepartment of Chemistry, University of Sydney, NSW 2006, Australia; bSchool of Chemistry, Monash University, Clayton, VIC 3800, Australia; cSchool of Physics and Materials Engineering, Monash University, Clayton, VIC 3800, Australia (g.halder@chem.usyd.edu.au)
Recently
there has been much speculation that molecular framework materials, like
coordination frameworks, may have the potential to emulate industrially
important porous materials such as zeolites. However, to date there have been few conclusive structural
reports, and the question as to what happens to the frameworks during
desolvation and resolvation remains unanswered. Here we report the first complete crystallographic study of
reversible guest-exchange in one such material, utilising a new type of single
crystal x-ray diffraction experiment.
The
robustness of the material M2(bpy)3(NO3)4.2(guest)
(M = NiII or CoII,
bpy = 4,4Õ-bipyridine) to guest-exchange has been well documented
[1,2], including the first single-crystal structural refinement of the fully
desolvated system. Presently we
have extended this work with in-situ single-crystal x‑ray diffraction experiments,
monitoring the uptake and release of a range of guest molecules into the host
framework (Figure 1). These
results represent the first of their kind and have yielded very unique information
on the structural consequences guest-exchange.
This
technique has been further implemented to study a range of nanoporous framework
materials, including a system that exhibits guest-dependent spin-state
switching [3].
References
1 Kepert, C.J. and Rosseinsky, M.J. (1999) Chem. Commun., 375-376.
2 Fletcher, A.J., Cussen, E.J., Prior, T.J., Rosseinsky, M.J., Kepert, C.J. and Thomas, K.M. (2001) J. Am. Chem. Soc. 123, 10001-10011.
3 Halder, G.J., Kepert, C.J., Moubaraki, B., Murray, K.S. and Cashion, J.D., (2002) Science 298, 1762-1765.