Browsing by Subject "Rotaxanes"
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- PublicationOpen AccessA Light-Driven Interlocked Catalyst(2018-03-06) Martinez-Cuezva, Alberto; Saura-Sanmartin, Adrian; Nicolas-Garcia, Tomas; Navarro, Cristian; Alajarín, Mateo; Berná Cánovas, José; Química OrgánicaThe synthesis of mechanical interlocked molecules has received increased attention over the last decades. The mechanical bond infers particular chemical properties to these systems. Particularly the study of their chemical activity is experiencing an important growth, remarking their use as catalysts. Herein we described the synthesis and application in catalysis of a photoswitchable interlocked shuttle.
- PublicationOpen AccessCopper-Linked Rotaxanes for the Building of Photoresponsive Metal Organic Frameworks with Controlled Cargo Delivery(American Chemical Society, 2020-07-09) Saura Sanmartín, Adrián; Martinez-Cuezva, Alberto; Bautista, Delia; Marzari, Mara R. B.; Martins, Marcos A. P.; Alajarín, Mateo; Berná, José; Berná, José; Química OrgánicaWe have prepared a photoresponsive metal–organic framework by using an amide-based [2]rotaxane as linker and copper(II) ions as metal nodes. The interlocked linker was obtained by the hydrogen bond-directed approach employing a fumaramide thread as template of the macrocyclic component, this latter incorporating two carboxyl groups. Single crystal X-ray diffraction analysis of the metal–organic framework, prepared under solvothermal conditions, showed the formation of stacked 2D rhombohedral grids forming channels decorated with the interlocked alkenyl threads. A series of metal–organic frameworks differing in the E/Z olefin ratio were prepared either by the previous isomerization of the linker or by postirradiation of the reticulated materials. By dynamic solid state 2H NMR measurements, using deuterium-labeled materials, we proved that the geometry of the olefinic axis of the interlocked struts determined the obtention of materials with different independent local dynamics as a result of the strength of the intercomponent noncovalent interactions. Moreover, the usefulness of these novel copper-rotaxane materials as molecular dosing containers has also been assayed by the diffusion and photorelease of p-benzoquinone, evaluated in different solvents and temperatures.
- PublicationOpen AccessEnantioselective Formation of 2-Azetidinones by Ring-Assisted Cyclization of Interlocked N-(alpha-Methyl)benzyl Fumaramides(WILEY-VCH VERLAG GMBH, 2018-04-16) Martinez-Cuezva, Alberto; Bautista, Delia; Alajarín, Mateo; Berná Cánovas, José; Química OrgánicaThe synthesis of optically active interlocked and non-interlocked 2-azetidinones by intramolecular cyclization of N-(alpha-methyl)benzyl fumaramide [2]rotaxanes is described. Two different strategies of asymmetric induction were tested in which the chiral group was located either proximal or distal to the reacting center of the thread. During these experiments, an interesting equilibration process inside the macrocyclic void occurred, thus leading to the cyclization through the (alpha-methyl)benzyl carbon atom and giving rise to beta-lactams, with a quaternary carbon atom, in an enantio- and diastereocontrolled manner. This cyclization also proceeds in kinetically stable chiral pseudo[2]rotaxanes, thus allowing further de threading to provide enantioenriched 3,4-disubstituted trans-2-azetidinones. The stereochemical outcomes of the cyclization inside and outside the macrocycle demonstrated noticeable
- PublicationOpen AccessExploring the Chemistry of the Mechanical Bond: Synthesis of a [2]Rotaxane through Multicomponent Reactions(American Chemical Society and Divisionof Chemical Education,Inc, 2023-08-01) Saura Sanmartín, Adrián; Lopez-Sanchez, Jorge; Lopez-Leonardo, Carmen; Pastor Vivero, Aurelia; Berná, José; Saura Sanmartín, Adrián; Berná, José; Química OrgánicaThe synthesis of a [2]rotaxane through three- or five-component coupling reactions has been adapted to an organic chemistry experiment for upper-division students. The experimental procedure addresses the search for the most favorable reaction conditions for the synthesis of the interlocked compound, which is obtained in a yield of up to 71%. Moreover, the interlocked nature of the rotaxane is proven by NMR spectroscopy. The content of the sessions has been designed on the basis of a proactive methodology whereby upper-division undergraduate students have a dynamic role. The laboratory experience not only introduces students to the chemistry of the mechanical bond but also reinforces their previous knowledge of basic organic laboratory procedures and their skills with structural elucidation techniques such as NMR and FT-IR spectroscopies. The experiment has been designed in such a customizable way that both experimental procedures and laboratory material can be adapted to a wide range of undergraduate course curricula.
- PublicationOpen AccessInterlocking the Catalyst: Thread versus Rotaxane-Mediated Enantiodivergent Michael Addition of Ketones to beta-Nitrostyrene(American Chemical Society, 2019-06-19) Martinez-Cuezva, Alberto; Marin-Luna, Marta; Alonso, Diego A.; Ros-Ñiguez, Diego; Alajarín, Mateo; Berná Cánovas, José; Química OrgánicaFumaramide threads bearing one l-prolinamide fragment have been designed as templates for promoting the efficient formation of novel Leigh’s [2]rotaxanes. Both threads and rotaxanes are shown to catalyze the asymmetric addition of ketones to β-nitrostyrene in an enantio- and diastereoselective manner. Interestingly, the enantioselective course of these processes is reversed simply by changing from thread to rotaxane as catalyst. DFT computations have allowed to rationalize the stereodivergence shown by the interlocked and noninterlocked catalysts.
- PublicationOpen AccessLight-responsive rotaxane-based materials: inducing motion in the solid state(Beilstein Institute for the Advancement of Chemical Sciences, 2023-06-14) Saura Sanmartín, Adrián; Saura Sanmartín, Adrián; Química OrgánicaLight-responsive rotaxane-based solid-state materials are ideal scaffolds in order to develop smart materials due to the properties provided by the mechanical bond, such as control over the dynamics of the components upon application of external stimuli. This perspective aims to highlight the relevance of these materials, by pointing out recent examples of photoresponsive materials prepared from a rotaxanated architecture in which motion of the counterparts and/or macroscopic motion of the interlocked materials are achieved. Although further development is needed, these materials are envisioned as privileged scaffolds which will be used for different advanced applications in the area of molecular machinery.
- PublicationOpen AccessMechanically interlocked profragrances for the controlled release of scents(ACS Publications, 2021-10-01) Lopez-Sanchez, Jorge; Alajarín, Mateo; Pastor, Aurelia; Berna Cánovas, José; Química OrgánicaThe synthesis of a series of interlocked profragrances and the study of the controlled release of the corresponding scents are reported. The structures of the profragrances are based on a [2]pseudorotaxane scaffold with a fumaramate thread derived from perfumery alcohols and a tetrabenzylamido ring. The delivery of the scents was accomplished by sequential thermal dethreading and further enzymatic hydrolysis. Alternatively, the dethreading can be achieved by increasing the polarity of the solvent or photochemical isomerization. The temperature of dethreading can be modulated by the steric demand of the ends of the thread, which allows the selection of different precursor structures depending on the desired rates of delivery. The inputs and outputs for the controlled release of the interlocked profragrances correspond to those of YES or AND logic gates.
- PublicationOpen AccessMolecular release by the rotaxane and pseudorotaxane approach(Wiley-VCH GmbH, 2025-03-06) Peñaranda-Navarro, Raquel; Collados-Salmerón, María; Carrilero-Flores, Elena; Saura Sanmartín, Adrián; Química OrgánicaThe controlled release of target molecules is a relevant application in several areas, such as medicine, fragrance chemistry and catalysis. Systems which pursue this implementation require a fine-tune of the start and rate of the release, among other properties. In this scenario, rotaxane- and pseudorotaxane-based systems are postulated as ideal scaffolds to accomplish a precise cargo release, due to the special features provided by the intertwined arrangement. This short review covers advances towards the controlled release of different molecules using rotaxane- and pseudorotaxane-based systems, both in solution and in the solid state.
- PublicationOpen AccessStereoselectivity in Michael Addition Reactions Mediated by Interlocked and Non-Interlocked Organocatalysts(2020-03-03) Puigcerver, Julio; Martinez-Cuezva, Alberto; Alonso, Diego A.; Marin-Luna, Marta; Ros-Ñiguez, Diego; Tomas, Jose L.; Alajarín, Mateo; Berná Cánovas, José; Química OrgánicaMechanically interlockedmolecules have became ideal candidates for their application in numerous fields, highlighting their use as molecularmachines. Recently the employment of rotaxanes as switchable catalysts has experienced a great grown. Herein, we describe the application of a series of polyamide-based non-interlocked and interlocked systems organocatalysts for the enantiodivergent Michael addition of ketones to β-nitrostyrene.
- PublicationOpen AccessThe Mobility of Homomeric Lasso- and Daisy Chain-Like Rotaxanes in Solution and in the Gas Phase as a Means to Study Structure and Switching Behaviour(Wiley-VCH, 2023-03-14) Saura Sanmartín, Adrián; Schalley, Christoph A.; Saura Sanmartín, Adrián; Química OrgánicaA precise structural determination of supramolecular architectures is a non-trivial challenge. This daunting task can be made even more difficult when interlocked species are to be analysed having macrocycles covalently equipped with a thread as repeating units, such as molecular lassos and daisy chains. When such functionalized macrocycles are included as scaffolds, different products having analogous NMR spectra as well as dynamic libraries can be obtained. Furthermore, if control over the motion of the parts relative to each other is to be achieved, a full understanding of the machinery's operation mechanism requires detailed insight into the structures involved. This understanding also helps designing improved synthetic molecular machines. Diffusion-ordered NMR spectroscopy and ion-mobility MS techniques are ideal tools to study such compounds in depth. This review covers recent examples on the use of the above-mentioned techniques to characterize these interlocked architectures.
- PublicationOpen AccessThe Role of Dethreading Process in Pseudorotaxanes and Rotaxanes towards Advanced Applications: Recent Examples(Wiley-VCH, 2023-02-06) Saura-Sanmartín, Adrián; Química OrgánicaRotaxanes are a type of mechanically interlocked molecules (MIMs), constituted by at least a thread surrounded by a wheel, which are widely employed in the research field of artificial molecular machines. Although applications retaining the integrity of the mechanical bond are usually reported, the dethreading of the components can be crucial to develop some advanced applications. Thus, different dethreading strategies have been reported, and advanced applications which require such a process have turned out to be suitable approaches towards machine-like operation. This review article covers recent examples of applications of pseudorotaxanes and rotaxanes in which dethreading processes have a key role to accomplish the desired function.