Biphenyl Bis(amino alcohol) Oxalamide Gelators: Complex Gelation Involving Coupled Equilibria, Central‐to‐Axial Chirality Transfer, Dia­stereoisomer Interconversion, and Self‐Sorting. Issue 6 (22nd January 2016)

• Record Type: Journal Article
• Authors: Portada, Tomislav; Molčanov, Krešimir; Šijaković Vujičić, Nataša; Žinić, Mladen
• Is Part Of: European journal of organic chemistry. Issue 6(2016)
• Page Start: 1205
• Page End: 1214
• Publication Date: 2016-01-22
• Subjects: Supramolecular chemistry -- Self‐assembly -- Chirality transfer -- Sol‐gel processes -- Gels; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201501261
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: Chiral gelators3 and4, with two valinol‐ or leucinol‐oxalamido arms attached to the 2, 2′‐positions of the proatropisomeric biphenyl group, were prepared, and their gels were studied. Compound ( R, R )‐3 in the solution and gel states forms a mixture of major [( R, aR, R )‐3 ] and minor [( R, aS, R )‐3 ] diastereomers due to central‐to‐axial chirality transfer. 1 H NMR studies of its toluene gel provide evidence of diastereomer interconversion and self‐sorting, which results in exclusive incorporation of ( R, aR, R )‐3 into the gel network. Gels formed in the 10 –3 M concentration range show an irregular T g /concentration dependence, which is in contrast to those formed in the 10 –2 M concentration range. The peculiar properties of the former gels may be explained by kinetic effects due to the presence of coupled equilibria comprising diastereomer interconversion and ( R, aR, R )‐3 self‐assembly where the rate of gelation becomes dependent on the rate of formation of the gelling ( R, aR, R )‐3 from the nongelling ( R, aS, R )‐3 . Abstract : Complex gelation behaviour involving coupled equilibria, diastereoselective self‐sorting, diastereomer interconversion, and central‐to‐axial chirality transfer is shown by some chiral biphenyl‐bis(amino alcohol) oxalamide gelators.