Ab initio study of metal-organic framework-5 Zn4O(1,4-benzenedicarboxylate)3:: An assessment of mechanical and spectroscopic properties

The electronic structure of porous metal-organic framework-5 (MOF-5) of composition Zn4O(1,4-benzenedicarboxylate)(3) was investigated with an ab initio density-functional-theory method. The unit cell volume and atomic positions were optimized with the well-known local-density approximation leading to a good agreement between the experimental and theoretical equilibrium structural parameters. Single crystal elastic constants (C-11, C-12, and C-44) were then computed at the athermal limit in order to estimate fundamental figures for technological and engineering applications. Our calculations suggest that MOF-5 behaves as a soft and ductile material with a Young's modulus of the order of Oak wood. Particular attention was also focused on the study of oxygen, and carbon K XANES spectra. The differences in their shapes and energy peak positions were discussed in relation to the bonding topology and to the different calculational methods used.