Isoreticular structures

Isoreticular structures a series of molecular architectures with identical network topologies but with different functionalities and dimensions... 

In the area of SBU chemistry, there is considerable effort being applied to the design of stmctures with the same skeleton but with different functionalities and dimensions. In this respect, a total number of sixteen isoreticular structures involving octahedral zinc acetate SBU and dicarboxylate linkers of varying length and ring substituents have been synthesized. Each structure exhibits the same network... 

Figure 6 Isoreticular structures having the same network topology hut with different linkers. (Reproduced fromN.L. Rosi, M. Eddaoudi, J. Kim, M. O Keeffe, O.M. Yaghi, CrystEngComm., 2002,4,401 by permission of Royal Society for Chemistry)...

An example of a porous framework that is isoreticular, but not isostructural, with MOF-5 is MOF-177, which incorporates the extended organic linker 1,3,5-benzenetribenzoate (BTB). The framework of crystalline MOF-177, Zn40(BTB)2- (DEF)i5(H20)3, where DEF = diethyl formamide, has an ordered structure with an estimated surface area of4,500 m2 g-1, which greatly exceeds those of zeolite Y (904 m2g 1) and carbon (2,030 m2 g-1). 

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.

A large number of MOFs have been synthesized and reported by researchers to date. Isoreticular metal-orgarric frameworks (IRMOFs) denoted as IRMOF-w ( = 1 through 7, 8, 10, 12, 14, and 16) are one of the most widely studied MOFs in the literature. These compounds possess cubic framework structures in whieh each member shares the same eubic topology [3, 21]. Figme 4 shows tire structure of IRMOF-l(MOF-5) as simplest member of IRMOF series. 

---