Interplay of Olefin Metathesis and Multiple Hydrogen Bonding Interactions: Covalently Cross-linked Zippers
作者:Jisen Zeng、Wei Wang、Pengchi Deng、Wen Feng、Jingjing Zhou、Yuanyou Yang、Lihua Yuan、Kazuhiro Yamato、Bing Gong
DOI:10.1021/ol201282d
日期:2011.8.5
Hydrogen-bonded zippers bearing terminal alkene groups were treated with Grubbs' catalyst, leading to covalently cross-linked zippers without violating H-bonding sequence specificity. The yield of a cross-linked zipper depended on the stability of its H-bonded precursor, with a weakly associating pair giving reasonable yields only at high concentrations while strongly associating pairs showed nearly quantitative yields. The Integration of thermodynamic (H-bonding) and kinetic (irreversible C=C bond formation) processes suggests the possibility of developing many different covalent association units for constructing molecular structures based on a self-assembling way.
Duplex Foldamers from Assembly Induced Folding
作者:Xiaowu Yang、Suzana Martinovic、Richard D. Smith、Bing Gong
DOI:10.1021/ja0361897
日期:2003.8.1
Oligoamide strands 1, 2, and 3, consisting of 4-H-bond units, were originally designed to form noncovalent polymers based on the expectation that they would adopt an extended conformation. Instead of assembling into the expected supramolecular polymer through their 4-H-bond units, the 1:1 mixture of 1 and 2 was found to form a highly stable dimeric species. To dimerize, the H-bonding sequences of 1 and 2 can only adopt a folded (stacked) conformation. The self-assembly of 3 was also found to adopt a similar folded duplex conformation. These novel duplex foldamers are very stable. They were characterized by 1D and 2D 1H NMR, VPO, and mass spectral (ESI) studies.