Isoreticular MOFs

IRMOF-m Isoreticular MOF (with n an integer referring to a member of the series). 

Eddaoudi, M., Kim, J., Rosi, N., et al., Systematic design of pore size and functionality in isoreticular MOFs and their application in methane storage. Science 2002, 295, 469 472. 

The isoreticular MOFs based on the Zn40(C0i)6 SBU also possesses favorable sorption properties for the storage of molecular hydrogen. At 77 K, microgravimetric sorption measurements gave H2 (mg/g) values of 13.2,15.0, 16.0, and 12.5 for IRMOF-1, IRMOF-8, IRMOF-11, and MOF-177, respectively. At the highest pressures attained in the measurements, the maximum uptake values for these frameworks are 5.0, 6.9, 9.3, and 7.1 molecules of H2 per Zn4OI unit where L stands for a linear dicarboxylate. 

Figure 1 Examples of two topologically distinct isoreticular MOF structures, (a) A cubic fragment of IRMOF-1. Each corner of the cubes is built up of a connector (b) and linked by a linker (c) (here 1,4-benzenedicarboxylate). The linkers form the edges of the cube. The connector can be described as four distorted tetrahedra Zn(01)30 connected by a central 02. (d) A cubic fragment of Cu-BTC (Cu3(BTC)2(H20)3 BTC 1,3,5-benzene-tricarboxylate) The structure is built up of the so-called paddle-wheels (e). Each metal atom completes its pseudo-octahedral coordination sphere, Cu(COO)2, with an aqua ligand.

M. Eddaoudi, J. Kin, N. Rosi, D. Vodak, J. Wachter, M. O Keeffe, and O.M. Yaghi, Systematic Design of Pore Size and Functionality in Isoreticular MOFs and their Application in Methane Storage. Science, 2002, 295, 469 -72. 

To determine the effect of OMSs within a MOF on H2 adsorption, Suh and coworkers synthesized three porous isoreticular MOFs (SNU-4, SNU-5, and SNU-5) with the same NbO-type net topology. The formation of OMSs can be controlled by precisely selecting different activation conditions. It was observed that in the presence of OMSs, the MOF clearly has a higher H2 adsorption on both gravimetric and volumetric bases, probably due to a stronger interaction between OMSs with H2 molecules, because the reduction of framework mass cannot completely explain the enhanced volumetric uptake. Note that for isostructural materials, volumetric capacity calculations can elucidate the effects of OMSs without discriminating against the additional mass. 

Organic linkers used in the isoreticular MOF (IRMOF) series. 

Llabres i Xamena FX, Abad A, Corma A, Garcia H. Isoreticular MOFs as efficient photocatalysts with tunable band gap an operando FTIR study of the photoinduced oxidation of propylene. J Catal 2007 250 294-8. 

Ti(0 Pr)4-functionalized MOFs increased with increasing channel sizes, probably due to the different diffusion rates of the organic substrates through the open channels of different sizes. Isoreticular MOFs thus represent a tunable platform for designing heterogeneous asymmetric catalysts that have uniform active catalytic sites, identical chiral environments, and controllable channel and pore size. 

---