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This account discusses the accidental discovery of self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers. Our laboratory never intended to make this discovery. At the time of this finding, our laboratory was interested in developing a methodology to mimic the self-assembly of helical rod-like and icosahedral or spherical viruses. An attempt to transform a monotropic biaxial nematic (Nb) phase of a compound constructed from a combination of a half-disc and a rod into an enantiotropic phase by attaching this building block as a side group to a polymer led to a polymer coated with a helical dendritic jacket appearing as a primitive rod-like virus. Investigation of more and less complex variants of the half-disc and rod compound led to the discovery of self-organizable dendrons, dendrimers, and dendronized polymers assembling into both helical rod-like and spherical helices supramolecular dendrimers. The combination of a disc-like and a rod-like compound that never exhibits the Nbphase was developed in France and published in this journal. Our discovery provided an example in which an incorrect assignment of a phase led to a finding that facilitated the development of several new unrelated research fields, all pioneered by self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers. We would like to use this opportunity to thank the scientists who elucidated the structure and the mechanism of self-assembly of viruses, the laboratory that developed the combination of disc-like and rod-like molecules, and the scientists who asked us to investigate this molecule for providing the inspiration for this discovery.
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Bridging organic, molecular, macromolecular, supramolecular and biological sciences to create functions via fluorine chemistry and fluorinated reagents
After a brief introduction highlighting the challenges of fluorine chemistry and the latest developments in the field, this Perspective will discuss how a combination of fluorine and fluorous chemistry together with fluorinated reagents helped to bridge between organic, molecular, macromolecular, supramolecular and biological sciences to create functions in the laboratory of the corresponding author. The reactivity of fluoride as a leaving group is best illustrated by SNAr reactions when it helped to demonstrate single electron transfer-mediated side reactions and through molecular design replaced activated aryl fluorides with aryl chlorides in the synthesis of poly(etherketone)s. Subsequently it was demonstrated how Ni(II) sigma complexes provided an orthogonal approach to the Suzuki-type cross-coupling of arylfluorides, other halides and all aryl C–O based electrophiles. Fluorinated reagents facilitated cylotrimetrization vs cyclotetramerization of bis(methoxy)benzyl chloride and alcohol and the synthesis of the simplest molecular liquid crystals. Triflic acid, methyl triflate facilitated the most tolerant living polymerizations including of cyclic siloxanes, functional vinyl ethers and oxazolines to generate self-organizable dendronized polymers while fluorine, trifluoromethyl and trifluoromethoxy groups facilitated disassembly and reassembly of liquid crystal polyethers and poly(p-phenylenes). Fluorinated stereocenters accessed the first heterochiral recognition in side-chain liquid crystal poly(vinyl ether)s and their model compounds. Alkali metal triflates mediated self-organization of supramolecular nonfluorinated and fluorinated self-assembling minidendrons, dendrons, dendrimers and self-organizable dendronized polymers. The role of fluorinated alkyl groups and of alkali metal triflates in the self-assembly, disassembly and isomorphic replacement analysis, of supramolecular helical columns, of the assembly of helical cogwheel coat and of spherical supramolecular dendrimers forming Frank-Kasper periodic and quasiperiodic arrays was highlighted. A brief discussion of fluorinated amino acids, peptides and peptoids and their potential role in the self-assembly and functions resulted from dendritic dipeptides followed by a discussion of semifluorinated amphiphilic Janus dendrimers as models of biological membranes, including for cell fusion and fission, concludes this Perspective.
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- Award ID(s):
- 2104554
- PAR ID:
- 10523918
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Giant
- Volume:
- 16
- Issue:
- C
- ISSN:
- 2666-5425
- Page Range / eLocation ID:
- 100193
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1016/j.giant.2023.100193
