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West NG, Bamford SE, Pigram PJ, Pan J, Qi DC, Mechler A. Controllable hierarchical self-assembly: systematic study forming metallosupramolecular frameworks on the basis of helical beta-oligoamides. MATERIALS HORIZONS 2023; 10:5584-5596. [PMID: 37815516 DOI: 10.1039/d3mh01327h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Self-assembly is a key guiding principle for the design of complex nanostructures. Substituted beta oligoamides offer versatile building blocks that can have inherent folding characteristics, offering geometrically defined functionalities that can specifically bind and assemble with predefined morphological characteristics. In this work hierarchical self-assembly is implemented based on metal coordinating helical beta-oligoamides crosslinked with transition metals selected for their favourable coordination geometries, Fe2+, Cu2+, Ni2+, Co2+, Zn2+, and two metalates, MoO42-, and WO42-. The oligoamide Ac-β3Aβ3Vβ3S-αHαHαH-β3Aβ3Vβ3A (3H) was designed to allow crosslinking via three distinct faces of the helical unit, with a possibility of forming three dimensional framework structures. Atomic force microscopy (AFM) confirmed the formation of specific morphologies that differ characteristically with each metal. X-Ray photoelectron spectroscopy (XPS) results reveal that the metal centres can be reduced in the final structures, confirming strong chemical interaction. Time of flight secondary ion mass spectrometry (ToF-SIMS) confirmed the spatial distribution of metals within the self-assembled networks, also revealing molecular fragments that confirm coordination to histidine and carboxyl moieties. The metalates MoO42- and WO42- were also able to induce the formation of specific superstructure morphologies. It was observed that assembly with either of nickel, copper, and molybdate form thin films, while cobalt, zinc, and tungstate produced specific three dimensional networks of oligoamides. Iron was found to form both a thin film and a complex hierarchical assembly with the 3H simultaneously. The design of the 3H substituted beta oligoamide to readily form metallosupramolecular frameworks was demonstrated with a range of metals and metalates with a degree of control over layer thicknesses as a function of the metal/metalate. The results validate and broaden the metallosupramolecular framework concept and establish a platform technology for the design of functional thin layer materials.
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Affiliation(s)
- Norton G West
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia.
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore.
| | - Sarah E Bamford
- Center for Materials and Surface Science, and Department of Mathematical and Physical Sciences, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Paul J Pigram
- Center for Materials and Surface Science, and Department of Mathematical and Physical Sciences, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Jisheng Pan
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore.
| | - Dong-Chen Qi
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland, 4001, Australia
| | - Adam Mechler
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia.
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Buchanan C, Hinds MG, Puskar L, Garvey CJ, Mechler A. Comprehensive multidimensional study of the self-assembly properties of a three residue substituted β3 oligoamide. PURE APPL CHEM 2021. [DOI: 10.1515/pac-2021-0324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Substituted β3 oligoamides form a unique self-assembling system where each monomer folds into a helix containing approximately three β3 amino acids per turn, yielding a geometrically well-defined cylindrical building block that, when N-acylated, is able to self-assemble head-to-tail into nanorods that can reach several 100 μm length. It was shown in previous works that self-assembly can be achieved with a three residue long oligoamide as well that lacks any intramolecular H-bonds, yet it crystallizes in a helix-like conformation. The self-assembly properties of these small oligoamides are however elusive, suggesting a more complex system than the self-assembly of the H-bond stabilized helical monomers. Here we focus on the self-assembly behaviour of a three residue oligoamide, Ac-β3[LIA] where the letters denote the side chain of the analogous α amino acid. Ac-β3[LIA] can yield highly inhomogeneous suspensions in water with a broad range of large fibrous structures that seem to be very stable, yet occasionally fibre growth is only observed upon heating. The small size of the monomer suggests a highly dynamic equilibrium yet all previous attempts failed to clearly identify low molecular weight species. Therefore a special methodology was employed in this study to characterize the suspensions at different size ranges: SANS that is optimal to measure the small oligomers and cross sectional diameter of the assemblies, DLS that is sensitive to the large populations and therefore the length of the superstructures, and NMR that is sensitive to monomeric and small oligomeric form, in conjunction with IR spectroscopy to probe the folding and AFM to image the morphology of the assemblies. Temperature ramping was used to perturb the system to probe the dynamicity of the self-assembly. It was found that the anomalous self-assembly behaviour of Ac-β3[LIA] is caused by its two stable conformations, a helix-building “horseshoe” fold and a linear conformer. The latter is exclusively found in monomeric form in solution whereas the horseshoe fold is stable in solid phase and in fibrous assemblies. Small oligomers were absent. Thus the self-assembly of Ac-β3[LIA] is arrested by the activation energy need of the conformation change; fibre growth might be triggered by conditions that allow increased conformational freedom of the monomers. This observation may be used to develop strategies for controlled switchable self-assembly.
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Affiliation(s)
- Claire Buchanan
- Department of Chemistry and Physics , Latrobe University , Bundoora , Australia
| | - Mark G. Hinds
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , Parkville , Australia
| | - Ljiljana Puskar
- Helmholtz Zentrum Berlin für Materialien und Energie GmbH , Berlin , Germany
| | - Christopher J. Garvey
- Lund Institute for Advanced Neutron and X-Ray Science , 223 70 Lund , Sweden
- Biofilm-Research Center for Biointerfaces and Biomedical Science Department , Faculty of Health and Society, Malmo University , 211 19 Malmo , Sweden
| | - Adam Mechler
- Department of Chemistry and Physics , Latrobe University , Bundoora , Australia
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Buchanan C, Garvey CJ, Puskar L, Perlmutter P, Mechler A. Coordination crosslinking of helical substituted oligoamide nanorods with Cu(II). Supramol Chem 2020. [DOI: 10.1080/10610278.2020.1730839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Claire Buchanan
- Department of Chemistry and Physics, La Trobe University, Bundoora, Australia
| | - Christopher J Garvey
- Australian Nuclear Science and Technology Organization (ANSTO), Lucas Heights, Australia
- Lund Institute for Advanced Neutron and X-ray Science (LINXS), Lund, Sweden
- Biofilms Research Center for Biointerfaces, Department of Biomedical Science, Health and Society, Malmö University, Malmö, Sweden
| | - Ljiljana Puskar
- Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany
| | - Patrick Perlmutter
- Department of Chemistry and Physics, La Trobe University, Bundoora, Australia
| | - Adam Mechler
- Department of Chemistry and Physics, La Trobe University, Bundoora, Australia
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