Diamondoid networks with interpenetration

In the complex [Cu(L)4]PF6 (L = 3-cyano-6-methylpyrid-2(lH)-one), the hydrogen-bonded linkage involves the amido R2(8) supramolecular synthon [Fig. 20.4.15(a)]. Each Cu(I) center serves as a tetrahedral node in a fourfold interpenetrated cationic diamondoid network. The tetrahedral metal cluster [Mn(/z3-OH)(CO)3]4 can be used to construct a diamondoid network with the linear 4,4/-bipyridine spacers [Fig. 20.4.15(b)],... 

Wuest has demonstrated that the pyridone moiety also generates a hydrogen-bonded supramolecular synthon that is suitable for building extended arrays.67 Remarkably, methanetetra(6-phenylethynyl-2-pyridone) exhibits a diamondoid network, sevenfold interpenetration and cavities large enough to enclathrate butyric or valeric acid.27 Wuest introduced the concept of tectons to describe molecules that inherently possess the molecular structure and intermolecular recognition features to predictably self-assemble into crystalline networks. He followed this study with several other examples of diamondoid networks sustained by the pyridone moiety 27c d... 

Finally, it should be noted that there are supramolecular synthons that do not rely upon hydrogen bonds. In this context, N—Br interactions were exploited to propagate a diamondoid network in the cocrystal formed by carbon tetrabromide and hexamethylenetetraaamine. This structure also represents a different but equally effective form of the modular approach two tetrahedral nodes with one possessing donor functionality and the other acceptor functionality only. The structure of the cocrystal formed by carbon tetrabromide and hexamethylenetetraaamine exhibits twofold interpenetration and does not enclathrate solvent or guest. 

Carlucci, L., Ciani, G., Proserpio, D. M., Rizzato, S., Three novel interpenetrating diamondoid networks from self-assembly of 1,12-dodecanedinitrile with silver(I) salts. Chem. Eur. J. 2002, 8, 1520-1526. 

A direct consequence of the existence of numerous low energy transverse vibrational modes in MOEs is that these materials exhibit extreme NTE behaviours. Among a range of cubic metal cyanide systems that display isotropic NTE, ° ° the interpenetrated diamondoid phases Zn(CN)2 and Cd(CN)2 have a = -16.9 x 10" and -20.4 x 10 respectively. The desorption of volatile guests from single diamondoid network Cd( CN)2 to achieve a 64 % porous apohost phase leads to the largest isotropic NTE yet reported for any material, with a = -33.5 x 10" K" (see Figure The thermal expansivity of this phase can be tuned... 

Figure 4 (a) Perspective views of the structure of a single adamantane cage with TUBA connections between cadmium ions, (b) View of the structure of 4d2DMF, showing the fourfold interpenetration of diamondoid networks. (Reprinted with permission from Ref 24. Copyright (2009) American Chemical Society.)... 

Another interesting case in crystal engineering is the one of interpenetrated cyano-bridged diamondoid networks. Zinc(II) easily adopts a tetrahedral geometry, so the solid-state structure of Zn(CN)2 is quite predictable tetrahedral zinc ions are connected by cyano groups generating a diamond-like net, with double interpenetration (Schemel). The cadmium derivative. 

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