Elucidating Negative Thermal Expansion in MOF-5
- Aarhus
Multi-temperature X-ray diffraction studies show that twisting, rotation, and libration cause negative thermal expansion (NTE) of the nanoporous metal-organic framework MOF-5, Zn{sub 4}O(1,4-benzenedicarboxylate){sub 3}. The near-linear lattice contraction is quantified in the temperature range 80-500 K using synchrotron powder X-ray diffraction. Vibrational motions causing the abnormal expansion behavior are evidenced by shortening of certain interatomic distances with increasing temperature according to single-crystal X-ray diffraction on a guest-free crystal over a broad temperature range. Detailed analysis of the atomic positional and displacement parameters suggests two contributions to cause the effect: (1) local twisting and vibrational motion of the carboxylate groups and (2) concerted transverse vibration of the linear linkers. The vibrational mechanism is confirmed by calculations of the dynamics in a molecular fragment of the framework.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1002912
- Journal Information:
- J. Phys. Chem. C, Vol. 114, Issue (39) ; 10, 2010; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Phase transition and negative thermal expansion of HfMnMo3O12
Incorporation of Pyrazine and Bipyridine Linkers with High-Spin Fe(II) and Co(II) in a Metal–Organic Framework