198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

Functional Organic Zeolite Analogues 135
cular O-H◊◊◊O hydrogen bonds in place of C-C covalent bonds as in diamond.
The resulting ice is necessarily a porous and hence low-density material, although
the parent diamond is the high-density hardest solid even known. Much
larger diamondoid lattices, e.g. 7 [31], 8 [32], 9 [33], 10 [34], 11 [35], 12 [36] and
13 [37] (Fig. 1) are obtained by using tetrahedral organic and inorganic components
such as 4,4¢,4¢¢,4¢¢¢-tetrasubstituted methane and 1,3,5,7-tetrasubstituted
adamantane derivatives and Cu I and Ag I centres, respectively. Rod-like spacers
or connectors can also be used. The resulting diamondoid huge cavities in
9 and 11 incorporate two molecules of well-ordered butyric acid and > 7.7 molecules
of disordered nitrobenzene and counter anion (BF 4 – ), respectively. Guest
binding does not occur in other cases, where two or more networks overlap in
such a way as to fill the cavities with each other. Such a self-inclusion can be prevented,
however, by modifying the building blocks so that interpenetration or
catenation of the networks becomes sterically less likely to occur [38, 39].
The PtS lattice contains both the square-planar (Pt) and tetrahedral (S)
centres. A square-planar Pt complex Pt(CN) 4 2– , when interconnected with tetrahedral
Cu I centres (CN◊◊◊Cu I ),affords an infinite network similar to the PtS structure
[40]. Tetra(4-pyridyl)- (3; X=N and M=Cu II ) and tetra(4-cyanophenyl)
porphyrin (3; X=C-CN and M=Cu II ) provide a huge square-planar site. They are
also assembled with Cu I (CuBF 4) to give a similar structure 14 having porphyrinwalled
channels in the two directions shown by the arrows (Fig. 2) [25].
14
Fig. 2. PtS-related structure of 3 ◊ CuBF 4 (X=N and M=Cu II in 3). The counteranion is not
shown for clarity. Identical channels (14) run in two directions shown by the arrows