Tuning of the Self‐Threading of Ring‐in‐Ring Structures in Aqueous Media

Neira, Iago; Alvariño, Cristina; Domarco, Olaya; Blanco, Víctor Francisco Sampedro; Peinador, Carlos; García, Marcos D.; Quintela, José M.

doi:10.1002/chem.201902851

Cited by 7 publications

(7 citation statements)

References 82 publications

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“…In another example of CDL, we have found how the C 1 Pd/Pt -MDSA of L 7 + , a slightly modified version of L 5 + owning swapped pyridinium and phenylene rings on its large side (Figure ), results in a molecular rectangle with a high propensity to self-complexation. , This tendency to the formation of ring-in-ring structures to minimize the solvent accessible surface of the metallacyclic analogues, has been also corroborated by using other fine-tuned analogues ( L 8 – 9 + ), owning enlarged hydrophobic aromatic groups on the middle portion of the large side of their L-shaped structures. Crucially, the speciation of these systems can be shifted by changing the concentration of the components, temperature, and polarity of the media or by addition of an appropriate guest for the metallacycle (Figure c).…”

Section: Pd(ii)/pt(ii)-directed Self-assembly Of “Blue Box” Analoguesmentioning

confidence: 62%

Dissecting the “Blue Box”: Self-Assembly Strategies for the Construction of Multipurpose Polycationic Cyclophanes

et al. 2020

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Metrics & MoreArticle Recommendations CONSPECTUS: Stoddart's "blue box" (B 4+ ), is one of the most iconic molecules in the recent history of chemistry. This rectangular tetracationic cyclophane has not only the ability to complex a wide variety of aromatic guests in organic or aqueous media, but because of the presence of viologen units on its structure, it also behaves as a redox-based molecular switch. In turn, B 4+ -based host−guest complexes can translate this responsiveness from the molecular to the supramolecular level, resulting in host-controlled binding. This unique behavior has allowed the development of a wide variety of B 4+ -containing (supra)molecular switches and machines, which certainly have inspired a whole generation of supramolecular chemists. Nevertheless, issues, such as synthetic accessibility, structural diversity, or the implementation of new chemical properties (luminescence, pH-or photo-responsiveness, etc.), have restricted somehow the development of new practical applications in the ever-changing realm of modern host−guest chemistry. Based largely on our own research throughout the past decade, we will highlight in this account two different strategies for the selfassembly of new B 4+ analogues: (1) Pd(II)/Pt(II) metal-directed self-assembly and (2) hydrazone-based dynamic covalent chemistry. In essence, the strategies are based on the substitution of inert C−C single bonds on the macrocycle by Pd/Pt−N or C N bonds of modifiable lability. In the case of the metal-directed synthesis, the use of Pd(II) centers allows for the spontaneous selfassembly at r.t., either in organic or aqueous media, of N-alkyl-4,4′-bipyridinium-based ligands into the desired metallacycles.Conversely, more inert Pt(II) salts can be also implemented, rendering the synthesis of more kinetically stable analogues. Alternatively, wholly organic B 4+ congeners can be produced in a modular fashion by using hydrazone-based dynamic covalent chemistry, allowing for the self-assembly in acidic water of macrocyclic pH-responsive molecular switches of adjustable kinetic stability.Owning pyridinium-based cavities of appropriate size, our B 4+ -inspired cyclophanes are able to complex aromatic substrates by a conjunction of the hydrophobic effect and π−π/C−H•••π interactions. Consequently, we will discuss in detail the different host− guest complexes that can be achieved using our cyclophanes. Considering this knowledge, the implementation of our B 4+ -based macrocycles onto mechanically interlocked molecules and knots will be introduced, as well as the development of practical applications for the hosts in currently important research fields, such as the development of duplex and G4-DNA binders, supramolecular catalysis or the sequestration of relevant pollutants. Finally, self-assembled hosts offer the unique opportunity to include constitutional dynamism into host−guest chemistry, so examples of the development by our group of stimuli-responsive constitutionally dynamic libraries and self-sorted systems will be highligh...

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Section: Pd(ii)/pt(ii)-directed Self-assembly Of “Blue Box” Analoguesmentioning

confidence: 62%

Dissecting the “Blue Box”: Self-Assembly Strategies for the Construction of Multipurpose Polycationic Cyclophanes

et al. 2020

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“…Other pyridinium-based ligands proved capable of generating water-soluble coordination assemblies. Peinador, Quintela, and co-workers prepared Pd II and Pt II water-soluble metallacycles and 2D receptors using this approach. − Mukherjee and co-workers presented water-soluble “molecular dice” ( 56 ) synthesized via coordination-driven self-assembly of flexible, cationic, tritopic ligand 55 (Figure a) . Likewise, Sun and co-workers reported the self-assembly of photochromic, redox-capable nanocapsule 58 made of four cis -blocked palladium corners and two pyridinium-functionalized tetratopic ligands ( 57 ), which contain two tris(4-pyridyl)-1,3,5-triazine bridged by a p -xylene linker (Figure b) …”

Section: Strategies For Aqueous Solubility and Stability Of Coordinat...mentioning

confidence: 99%

Design and Applications of Water-Soluble Coordination Cages

2020

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Compartmentalization of the aqueous space within a cell is necessary for life. In similar fashion to the nanometer-scale compartments in living systems, synthetic water-soluble coordination cages (WSCCs) can isolate guest molecules and host chemical transformations. Such cages thus show promise in biological, medical, environmental, and industrial domains. This review highlights examples of three-dimensional synthetic WSCCs, offering perspectives so as to enhance their design and applications. Strategies are presented that address key challenges for the preparation of coordination cages that are soluble and stable in water. The peculiarities of guest binding in aqueous media are examined, highlighting amplified binding in water, changing guest properties, and the recognition of specific molecular targets. The properties of WSCC hosts associated with biomedical applications, and their use as vessels to carry out chemical reactions in water, are also presented. These examples sketch a blueprint for the preparation of new metal–organic containers for use in aqueous solution, as well as guidelines for the engineering of new applications in water.

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“…In addition, hydrophobic effects were exploited by Quintela and co-workers to promote the threading of two metallacycles in a ring-in-ring fashion. , Using a 1,4-biphenylene-bridged 4,4′-bipyridinium-based ligand and cis-protected Pd(II)/Pd(II) metal centers, a [4Pd + 4L] ring-in-ring complex was constructed in aqueous solution. Concentration, temperature, and solvent polarity were reported to affect the speciation in this metal-directed self-assembly process.…”

Section: Ring-in-ring Complexesmentioning

confidence: 99%

Coordination-Directed Construction of Molecular Links

et al. 2020

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Since the emergence of the concept of chemical topology, interlocked molecular assemblies have graduated from academic curiosities and poorly defined species to become synthetic realities. Coordination-directed synthesis provides powerful, diverse, and increasingly sophisticated protocols for accessing interlocked molecules. Originally, metal ions were employed solely as templates to gather and position building blocks in entwined or threaded arrangements. Recently, metal centers have increasingly featured within the backbones of the integral structural elements, which in turn use noncovalent interactions to self-assemble into intricate topologies. By outlining ingenious recent examples as well as seminal classic cases, this Review focuses on the role of metal−ligand paradigms in assembling molecular links. In addition, the ever-evolving approaches to efficient assembly, the structural features of the resulting architectures, and their prospects for the future are also presented.

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Tuning of the Self‐Threading of Ring‐in‐Ring Structures in Aqueous Media

Cited by 7 publications

References 82 publications

Dissecting the “Blue Box”: Self-Assembly Strategies for the Construction of Multipurpose Polycationic Cyclophanes

Dissecting the “Blue Box”: Self-Assembly Strategies for the Construction of Multipurpose Polycationic Cyclophanes

Design and Applications of Water-Soluble Coordination Cages

Coordination-Directed Construction of Molecular Links

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