Metallomacrocycle

Other supramolecular structures such as catenanes and rotaxanes can be formed using zinc as a template ion for example, a benzylic imine catenate formed by Leigh et a/.288 The reversible five-component assembly of a [2]catenane from a chiral metallomacrocycle and a dinaphtho-crown ether has been achieved. Zinc is used as the metal component and drives assembly via the coordination to a bipyridyl unit 7r interactions between the aromatic components are also... 

Molecular Recognition of Neutral and Charged Guests using Metallomacrocyclic Hosts Ivan V. Korendovych, Rebecca A. Roesner and Elena V. Rybak-Akimova... 

Peripherally Functionalized Porphyrazines Novel Metallomacrocycles with Broad, Untapped Potential... 

Wang P, Mooiefield CN, Newkome GR. Nanofabrication teversible self-assembly of an imbedded hexameric metallomacrocycle within a macromolecular superstructure. Angew Chem Int Ed 2005 44 1679-1683. 

Numerous metallomacrocycles self-assemble from their components giving species possessing various structures, for instance triangular shape [9.30,9.31] containing a cavity [9.32], which may include a guest molecule [9.33] square [9.34,9.35] or star like [9.36-9.39] shapes wheel-shaped or toroidal hexameric [9.40], octameric [9.41] or decameric [9.42,9.43] structures square [9.44,9.45] rectangular [9.46,9.47] or bent [9.48] boxes into which substrate molecules may bind [9.49,9.50] adaman-tanoid shape [9.51,9.52] with cation inclusion [9.51c], formally related to that of the spheroidal macrotricycle 21 catenane type [9.53]. Coordination species of dendri-mer or arborol nature have been constructed [7.61, 8.27, 9.54]. 

The chemical flexibility of the porphyrin-like metallomacrocycles has been used to vary the electronic properties of the molecular units and hence the resulting solid. This has been brought about by the choice of the basic ligand, the peripheral substituents and the central metal. The main variants on the porphyrin skeleton are shown in Figure 8. A large number of compounds have been obtained as conducting polycrystalline powders by oxidation of the parent metallo-macrocycle with iodine.90 Table 4 contains details of compounds which have been obtained as single crystals and have been extensively characterized and studied. 

Figure 7.48 Structures of imidazole-derived metallomacrocycles and crystal structure of the water/ methanol inclusion complex of 7.67.61...

In structures like A-C rather large peptide domains are conformationally fixed by coordination to metals. Smaller domains can also be obtained, however (Figure 1.3.4) [11]. Extensive NMR studies of the metallomacrocycle D show that an a-helical structure is adopted by the Ac-His-Ala-Ala-Ala-His-NH2 pentapeptide on binding to the (en)Pd-fragment (en = ethylene diamine). The peptidic part of D represents one single turn of the helix [12]. 

Scheme 10.25 [2]Catenane formation by metallomacrocyclic clipping reported by Quintela and coworkers.

Scheme 10.26 Metallomacrocyclic/[2]catenane formation templated by second-sphere coordination of the PdCI2 subunit reported by Wisner and coworkers.

Liang XY et al (2002) Structure and dynamics of metallomacrocycles Recognition of zinc xylyl-bicyclam by an HIV coreceptor. J Am Chem Soc 124 9105-9112... 

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