Supramolecular Arrays of Metal Ions. Racks, Ladders, Grids

3 Supramolecular Arrays of Metal Ions. Racks, Ladders, Grids 

Various other inorganic superstructures may be imagined and selected as goal for self-assembly. 

A rack-like arrangement schematically represented by 160, would be formed by the complexation of several metal ions to rigid, linear sequences of binding sites. Thus, binding of bipy or phen units to 155 and to its extended tri- and tetratopic analogues present in 157 and in 158 via metal ions of tetrahedral coordination such as Cu(l) and Ag(l) should yield rack structures of type 160. With the bipy or phen unit included in a macrocycle, inorganic rotaxane-type structures (see also Section 9.6) such as 159 have been obtained [9.97a]. A linear sequence of connected terpy sites such as 161 yields racks with individual terpy units and metal ions of octahedral coordination [9.97b]. 

Ladder superstructures 162 may result from the complexation of linear ligands of the type of 155 and bispyrimidine derivatives 163 or extended units 164 with 

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