One of the challenges in the realization of synthetic oligomers capable of sequence-selective duplex formation is intramolecular folding interaction between complementary recognition units. To assess whether complementary hetero-oligomers can assemble into high fidelity duplex structures, the competing folding equilibria must be carefully considered. A family of recognition-encoded aniline oligomers were assembledviareductive amination of dianiline linkers and dialdehyde monomers, which were equipped with either a 2-trifluoromethylphenol or a phosphine oxide H-bond recognition unit. To test the possibility of 1,2-folding in mixed sequence oligomers, the self-assembly properties of the homo- and hetero-dimers were characterised by19F and1H NMR titration and dilution experiments in toluene and in chloroform. Three different systems were investigated with variations in the steric bulk around the H-bond acceptor unit and the length of the dianiline linker. For two systems, the hetero-dimers folded with intramolecular H-bonding in the monomeric state, reducing stability of the intermolecular duplex by two to three orders of magnitude compared with the corresponding homo-oligomers. However, the use of a long rigid linker as the backbone connecting two monomer units successfully prevents 1,2-folding and leads to the formation of a stable mixed sequence duplex in toluene.

Duplexvs.folding: tuning the self-assembly of synthetic recognition-encoded aniline oligomers

Rosa-Gastaldo D.;Hunter C. A.;Gabrielli L.
2021

Abstract

One of the challenges in the realization of synthetic oligomers capable of sequence-selective duplex formation is intramolecular folding interaction between complementary recognition units. To assess whether complementary hetero-oligomers can assemble into high fidelity duplex structures, the competing folding equilibria must be carefully considered. A family of recognition-encoded aniline oligomers were assembledviareductive amination of dianiline linkers and dialdehyde monomers, which were equipped with either a 2-trifluoromethylphenol or a phosphine oxide H-bond recognition unit. To test the possibility of 1,2-folding in mixed sequence oligomers, the self-assembly properties of the homo- and hetero-dimers were characterised by19F and1H NMR titration and dilution experiments in toluene and in chloroform. Three different systems were investigated with variations in the steric bulk around the H-bond acceptor unit and the length of the dianiline linker. For two systems, the hetero-dimers folded with intramolecular H-bonding in the monomeric state, reducing stability of the intermolecular duplex by two to three orders of magnitude compared with the corresponding homo-oligomers. However, the use of a long rigid linker as the backbone connecting two monomer units successfully prevents 1,2-folding and leads to the formation of a stable mixed sequence duplex in toluene.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3439914
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