Cyclobutane scaffold in bolaamphiphiles : Effect of diastereoisomerism and regiochemistry on their surface activity aggregate structure
Pi i Boleda, Bernat (Universitat Autònoma de Barcelona. Departament de Química)
Sorrenti, Alessandro (Universitat Autònoma de Barcelona. Departament de Química)
Sans, Marta (Universitat Autònoma de Barcelona. Departament de Química)
Illa, Ona (Universitat Autònoma de Barcelona. Departament de Química)
Pons, Ramon (Institut de Química Avançada de Catalunya. Departament de Tecnologia Química i de Tensioactius)
Branchadell Gallo, Vicenç (Universitat Autònoma de Barcelona. Departament de Química)
Ortuño Mingarro, Rosa María (Universitat Autònoma de Barcelona. Departament de Química)

Data:	2018
Resum:	Cationic bolaamphiphiles have been synthesized starting from meso cis- or chiral trans-1,2-difunctionalized cyclobutane derivatives. They include cis/trans pairs of diastereoisomers, of N- or C-centered bisamides. The goal of this work was to investigate the influence of stereochemistry and regiochemistry on their abilities as surfactants and self-assembly. Very large differences in surface coverage (2-fold), critical micellar concentration (cmc, up to 2 orders of magnitude), and aggregate structure (from lamellae to fibers) for the four molecules are remarkable due to regio- and stereochemistry differences. Computational calculations were carried out to rationalize the experimental findings and a new methodology has been developed to calculate the structure of these bolaamphiphiles at the surface. Although the four surfactants adopt a wicket-like conformation, for N-centered trans, the distance between polar heads is much larger than that for the other three molecules, as suggested by calculations. We have shown that the interplay between the regiochemistry and stereoisomerism, enhanced by rigidity of the cyclobutane ring, affects different physicochemical properties quite differently. That is, the cmc value is mainly governed by stereochemistry, with regiochemistry only modulating this value. On the other hand, regiochemistry definitely governs the morphology of the supramolecular aggregates (i. e. , long fibers versus plates or spherical assemblies), with stereochemistry finely modulating their structural parameters. All these results must help in the rational design of new bolaamphiphiles with predictable properties and useful potential applications.
Ajuts:	Ministerio de Economía y Competitividad CTQ2016-77978-R Agencia Estatal de Investigación CTQ2017-88948-P
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Surfactant ; SAXS ; Cyclobutane ; Bolaamphiphile ; Aggregation ; Diastereoisomerism ; Regiochemistry
Publicat a:	Langmuir, Vol. 34, Issue 38 (September 2018) , p. 11424-11432, ISSN 1520-5827

DOI: 10.1021/acs.langmuir.8b01462

Postprint 31 p, 1.1 MB

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