Diamondoid nets

L= l,2-bis(2-pyrimidinylthio)ethane), the large macrocyclic size leads to the interpenetration of the diamondoid nets and a host-guest arrangement of the ligands within the cycles. 

In the analysis of the topology of such nets we can look for a classification scheme that will allow one to uniquely assign equal nets (up to isomorphism) derived from totally different crystal structures. Remember that the topology is not influenced by the metrical properties of the structure (angles, distances), so that a 4-connected diamondoid net is such, even if highly distorted (the geometry around the nodes could be far from tetrahedral), and also, obviously, is not dependent on the chemical nature of each node/vertex. 

Figure 1.3.6 The highly distorted diamondoid net observed in the 2-fold interpenetrated structure of SbCI3(p-diacetylbenzene) with a diamondoid cage in black (W. A. Baker, D. E. Williams, Acta Crystallogr., Sect. B 1978, 34, 1111) (left). The observed diamondoid cage (center) is compared with the undistorted adamantane cage as in diamond (right).

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... 

Under hydro(solvo)thermal conditions, Cd and Zn coordination networks ean be obtained by reactions of metal salts with cyanopyridine or pyiidinecarboxaldehyde. Cyano-, carboxal-dehyde-, and ester-substituents slowly hydrolyze to form corresponding earboxylie acid facilitating network formation. For instance, bis[4- 2-(4-pyridyl)ethenyl benzoato]-Zn° and Cd with eightfold diamondoid network structures were obtained by slow hydrolysis of (E)-4-(4-cyanos-tyryl)pyridine under hydro(solvo)thermal conditions (3-D diamondoid net Scheme 6a). ... 

Figure 15 Examples of (a) diamondoid nets from a tetrahedral copper(I) center and 4,4 -bipyridine (XACHAO) and (b) a cubic (PtS) lattice from octahedral coppo-(ll) nodes and 4,4 -bipyridine ligands (GORWUF). In the latter case, the lattice is completed by bridging SiFg anions linking togetha- the 2D array of Cn(4,4 -bpy)2) sheets.

Figure 19 Typical representations of 3D interpenetrated structures involving (a) the (3.5) net, (b) the a-Po net, (c) diamondoid nets, and (d) rutile nets. (Redrawn by Dr. S. Batten from Ref. 44.)...

Keywords Diamondoid net Metal-organic framework Noncentrosymmetric MOFs Nonlinear optics Octupolar symmetry Push-pull effect Second harmonic generation... 

Fig. 2 A 3D diamondoid net of [Zn(inic)2] built from Za tetrahedral connecting points and p-pyridinecarboxylate linkers. After [12]...

Fig. 3 (a) Asymmetric unit representation of [Zn(aptz)2] showing that the Zn center displays a slightly distorted tetrahedron. After [23]. (b) A non-interpenetration diamondoid net of [Zn(aptz)2]. After [23]... 

Fig. 11 (a) Polyhedral view of the 3D anionic framework of [CdLi(oba)2] . (b) View of the Li -omitted fivefold interpenetrating diamondoid framework, (c) The catenation of the six-membered rings of five individual diamondoid nets. Reprinted with permission from [16] Copyright 2010 American Chemical Society... 

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