Hydrazone exchange: a viable route for the solid-tethered synthesis of [2]rotaxanes

Rodrigues, Rafael Da Silva; Luis, Ena T.; Marshall, David L.; McMurtrie, John C.; Mullen, Kathleen M.

doi:10.1039/d1nj00388g

Cited by 4 publications

(3 citation statements)

References 87 publications

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“…Our main synthetic approaches are shown in Scheme 2. Normally, ethyl carbamates can be cleaved in water under the exposure of a base at elevated temperature or of a strong acid [33–34] . However, our system was only deprotonated under basic conditions and the carbamate protecting group could not be removed.…”

Section: Resultsmentioning

confidence: 99%

1‐Nitrimino‐5‐azidotetrazole: Extending Energetic Tetrazole Chemistry

2022

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Azide and nitrimino functions are among the most energetic substituents that can be introduced to the skeleton to enhance the energetic properties of a compound. In this study, we report the successful synthesis of a compound that combines both, azide and nitrimino substituents directly attached to one tetrazole scaffold. 1-Nitrimino-5-azidotetrazole is prepared by nitration of 1-amino-5-azidotetrazole. Subsequent salination with ammonia and guanidinium carbonate yields two highly energetic derivatives. All energetic compounds, as well as the intermediate steps of an alternatively developed synthesis strategy, were analysed and characterized in detail. In addition to multinuclear NMR and IR spectroscopy, crystal structures of all key compounds were measured. The sensitivities (friction, impact, electrostatic discharge and thermal) were determined accordingly. In addition, the detonation parameters of all energetic substances were calculated with the EXPLO5 code, which was fed with the enthalpy of formation (atomization method based on CBS-4M) and the crystallographic densities.

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Section: Resultsmentioning

confidence: 99%

1‐Nitrimino‐5‐azidotetrazole: Extending Energetic Tetrazole Chemistry

2022

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“…However, the potential of this synthetic method could be overshadowed by the need for the separation of the amplified product from the reaction mixture. A similar approach was also used by Mullen et al [34] . demonstrating that hydrazone exchange, under thermodynamic control, can be used to improve the synthesis of rotaxanes in solution and to pattern polymer resin beads with rotaxanes.…”

Section: Synthetic Methodologies For Hydrazone‐based Systemsmentioning

confidence: 96%

Versatility of the Amino Group in Hydrazone‐Based Molecular and Supramolecular Systems

et al. 2022

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Hydrazone‐based systems have been, and continue to be, widely studied in the field of supramolecular chemistry due to the chemical versatility of their triatomic C=N‐N structure, whose amino nitrogen commonly bears a methyl group or a hydrogen atom. Herein we review the conformational, configurational, and constitutional dynamics of these systems, focusing on the particularly important role of the N−H group of the hydrazone framework in each of those processes observed in molecular and supramolecular systems published in recent decades. Due to the enormous diversity of supramolecular architectures and molecular entities, the most representative synthetic methodologies to obtain them are described.

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“…However, the rotaxane equilibrium in this system is always complicated, because the symmetrical nature of disulfide exchange also led to appearance of non‐polymer bound [2]‐ and [3]rotaxanes as a result of homo‐ rather than hetero‐coupling. To solve this issue, the authors next tried the same polymer‐functionalization using the unsymmetrical hydrazone linkage [94] . This approach led to excellent surface functionalization selectivity and yield (around 80 %) in the reaction of aldehyde‐capped pseudorotaxanes with hydrazine‐functionalized TentaGel polymer resins.…”

Section: Dynamic Capping Chemistrymentioning

confidence: 99%

Dynamic Covalent Chemistry for Synthesis and Co‐conformational Control of Mechanically Interlocked Molecules

Gaedke

Schaufelberger

2022

Eur J Org Chem

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Mechanically interlocked molecules have found extensive applications in areas all across the physical sciences, from materials to catalysis and sensing. However, introducing mechanical bonds and entanglements at the molecular level is still a significant challenge due to the inherent restriction in entropy needed to preorganize strands before interlocking. Over the last decade, dynamic covalent chemistry has emerged as one of the most efficient methods of forming rotaxanes, catenanes and molecular knots. By using reversible bonds such as imines, disulfides and boronate esters, one can use the inherent error‐correction in these linkages to form interlocked architectures with high fidelity and often in excellent yields. This review reports on recent advances in the use of dynamic covalent chemistry to make mechanically interlocked molecules, systematically surveying clipping, capping and templating approaches with dynamic bonds. Furthermore, it is also discussed how dynamic bonds can be used to control motion, co‐conformational expression and catalytic activity in mechanically interlocked molecular machinery.

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Hydrazone exchange: a viable route for the solid-tethered synthesis of [2]rotaxanes

Abstract: Controlled and complete assembly of supramolecular systems on solid supports is a challenge that would elevate the function of interlocked architectures. Building on the success of other dynamic covalent synthetic...

Cited by 4 publications

References 87 publications

1‐Nitrimino‐5‐azidotetrazole: Extending Energetic Tetrazole Chemistry

1‐Nitrimino‐5‐azidotetrazole: Extending Energetic Tetrazole Chemistry

Versatility of the Amino Group in Hydrazone‐Based Molecular and Supramolecular Systems

Dynamic Covalent Chemistry for Synthesis and Co‐conformational Control of Mechanically Interlocked Molecules

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