Phenylene ethynylene foldamers

Haley MM, Pak JJ, Brand SC (1999) Top Curr Chem 201 81 HOger S (1999) J Polym Sci A Polym Chem 37 2685 Bunz UHF, Rubin Y, Tobe Y (1999) Chem Soc Rev 28 107 Faust R (1998) Angew Chem Int Ed 37 2825 Moore JS (1997) Acc Chem Res 30 402 Zhao D, Moore JS (2003) Chem Commun 807 Nelson JC,Saven JG,Moore JS,Wolynes PG (1997) Science 277 1793 Shetty AS, Zhang J, Moore JS (1996) J Am Chem Soc 118 1019 Prince RB,Saven JG,Wolynes PG,Moore JS (1999) J Am Chem Soc 121 3114 Hill DJ, Moore JS (2002) Proc Natl Acad Sci USA 99 5053 Cantor CR, Schimmel PR (1980) Biophysical chemistry. Freeman, San Francisco Prince RB (2000) Phenylene ethynylene foldamers cooperative conformational transition, twist sense bias, molecular recognition properties, and solid-state organization. PhD thesis. University of Illinois at Urbana-Champaign... 

Ryan B. Prince was born in Robbinsdale, MN, in 1972. He graduated from Southeast Missouri State University in 1995 with his B.S. degree in Chemistry, where he worked for Professor Jin K. Gong on the synthesis and characterization of transition-metal complexes that bind and activate carbon dioxide. He then went to the University of Illinois and worked with Professor Jeffrey S. Moore on the synthesis and study of oligo(m-phenylene ethynylene) foldamers. He completed his Ph.D. degree in Organic Chemistry in 2000 and is currently a senior research chemist at 3M Company in St. Paul, MN. 

Using protective groups strategies and coupling conditions similar to those described for the synthesis of OmPEs, oligofortho-phenylene ethynylene)s (OoPEs) were also synthesized (Scheme 9.3) [4]. However, in contrast to their meta-linked counterparts, the synthesis of ortho-linked phenylene ethynylenes foldamers has been limited to oligomers with only six repeat units. 

Convergent synthesis strategies allow production of longer oligomers than are practically obtainable with stepwise synthesis. These strategies may be employed in conjunction with either solid-phase or solution synthesis. Phenylene ethynylene foldamers have been synthesized by... 

A foldamer-based molecular recognition system that has enantiomeric M and P helical conformation was also studied. The diastereoselective complexation of an achiral, amphiphilic, helical m-phenylene ethynylene dodecamer 13 with a chiral plant natural product a-pinene 14 was demonstrated by ICD studies (Figure 10). The stoichiometry of the complex was determined as 1 1 by CD titration measurements based on the linearity of a Benesi-Hildebrand plot and the slope of a Hill plot. The association constant was estimated to be = 6.83 x 10" indicating that 13 can capture 14 efficiently. The results suggested that the chiral guest can stabilize one of the oligomer s enantiomeric helical M or P conformations. 

Like the mPE foldamers, orf/to-substituted phenylene ethynylene (oPE) oligomers adopt helically folded conformations in acetonitrile. " As a result of the 60° angle imposed by the ortho-connectivity, only three units are... 

Another foldamer strategy involves oligo(phenylene ethynylene) structures that fold into helical conformations, creating tubular cavities. The folding is driven primarily by solvophobic effects—the nonpolar aromatic portions want to get away from the polar solvent, while the polar ethylene oxide side chains are exposed. Favorable aromatic-aromatic interactions may also be involved. These helical structures resemble a common protein motif—the a/ (3-barrel—and are also promising scaffolds for future study. 

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