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.