Interpenetrated structures coordination polymers

The structure of coordination polymers formed with 3,6-bis(pyridin-3-yl)-l,2,4,5-tetrazine and zinc salts can be controlled by the choice of alcoholic solvents. Infinite lattice compounds of the form [Zn2L2(N03)4(Me0H)2(//-L)] and [Zn2(/U-L)3(N03)4](CH2C12)2) have been structurally characterized. The former structure shows an alternating single- and double-bridged species whereas the latter exists as a non-interpenetrated ladder complex.273... 

Mir MH, Koh LL, Tan GK, Vittal JJ (2010) Single-crystal to single-crystal photochemical structural transformations of interpenetrated 3D coordination polymers by [2-1-2] cycloaddition reactions. Angew Chem Int Ed Engl 49 390-393... 

A number of cyano-bridged coordination polymers with Prussian Blue-related structures, in which extended linear Ag(CN)2 or AufCNH bridges take the place of the OT bridges of the prototype, show 3-fold interpenetration [1]. A typical example is that of Rb[Cd Ag(CN)2)3] consisting of Rb+ cations and a 3-fold interpenetrating polymeric anion, whose structure is shown in Figure 31. 

Figure 2.4.5 Unusual structural arrangements can be observed for coordination polymers including (a) interpenetration, or polycatenation, and (b) self-entanglement.

A survey of 301 interpenetrated structures in the CSD and ICSD was undertaken in 2004 which showed the distribution of structure types given in Figure 9.34. The 3D diamondoid net with its large adamantoid cavities proved to be by far the most common interpenetrated solid. For coordination polymers the highest degree of interpenetration is 10-fold and occurs for a silver(l) complex of... 

Figure 7-14. Classification of interpenetrating coordination polymers a and b one-dimensional linear structures c and d two-dimensional interpenetration of ladders e and f three-dimensional interpenetration of undulating and multiple layers.

The enormous variety of metal-ligand geometries available to coordination polymers results in countless possible open and porous frameworks. (There are few limitations to this approach, but when more than one apparently very open framework exhibits interpenetration, in which the free volume of one framework is filled by one or more similar frameworks, the result is often a non-porous solid (although even then some interpenetrating structures demonstrate small-pore microporosity between the different frameworks)). 

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