Macrocycle Design

Transition Metal and Organic Redox-Active Macrocycles Designed to Electrochemically Recognize Charged and Neutral Guest Species Paul D. Beer... 

A number of other synthetic ion channels have been developed that incorporate crown ethers as critical elements. They cannot all be described and illustrated in this short chapter but it is important to note them. Voyer and coworkers developed channels that use an a-helical backbone to align a series of crowns into a channel that was both functional and biologically active (Voyer and Robataille, 1995 Voyer et al., 1997). Pechulis and coworkers developed a channel in which a central crown used tartaric acid subunits to anchor steroids, which formed the channel s walls (Pechulis et al., 1997). Mendoza and coworkers prepared an active channel based on a calixaiene central unit but that had crown ether headgroups (de Mendoza et al., 1998). Hall and coworkers modified the tris(macrocycle) design originating in our lab to form a redox-switchable crown that was active in bilayers (Hall et al., 1999, 2003). 

TRANSITION METAL AND ORGANIC REDOX-ACTIVE MACROCYCLES DESIGNED TO ELECTROCHEMICALLY RECOGNIZE CHARGED AND NEUTRAL GUEST SPECIES... 

An indole-terminated tris(macrocycle) designed to be a channel-former and which is an effective carrier in bulk membranes but fails to function in a lipid bilayer owing to hydrogen-bond formation has been described <1996CC2147>. Tryptophan- and tryptamine-derived tetraazacyclooctadecane macrocycles have been synthesized <1996J(P1)2427>. Transannular hydrogen bonding stabilizes a left-handed double-helical conformation of the... 

P. G. Potvin and J.-M. Lehn, in Synthesis of Macrocycles Design of Selective Complexing Agents (R. M. Izatt and J. J. Christensen, eds.), John Wiley Sons, New York, 1987, p. 167. 

In addition to macrocycle design, symmetry analysis would also be useful for chain analysis, both to choose chain members and to place zigzags. Symmetry analysis should also be consulted for molecular rotation (see prior section on Making Rings and Chains Horizontal or Symmetrical). Geometrical symmetry perception, though nebulous as described here, probably constitutes the greatest unexploited tool in SDG. 

Karasik AA, Balueva AS, Naumov RN et al (2008) An effective methodology of P,N-macrocycles design. Phosphorus Sulfur Silicon Relat Elem 183 583-585... 

---