Covalent mechanochemistry

Ribas-Arino J, Marx D (2012) Covalent mechanochemistry theoretical concepts and computational tools with applications to molecular nanomechanics. Chem Rev 112 5412... 

Ribas-Arino J, Shiga M, Marx D (2009) Understanding covalent mechanochemistry. Angew Chem Int Ed Engl 48 4190-4193... 

Ribas-Arino J, Marx D (2012) Covalent mechanochemistry theoretical concepts and computational tools with applications to molecular nanomechanics. Chem Rev 112 5412-5487 Kildishev AV, Boltasseva A, Shalaev VM (2013) Planar photonics with metasurfaces. Science 339 1232009. doi 10.1126/science.l232009... 

Why there is an growing interest in a covalent mechanochemistry (CMC) [16-18]. Mostly because of the potential use of such smart materials in applications that range from drug delivery to camouflage systems and self-healing materials [19, 20]. At this moment it is hard to overestimate the potential and importance of mechanochemistry as it has a great impact in different fields such as synthetic chemistry and materials science [21]. 

S.N. Zhurov, Mechanochemistry The mechanical activation of covalent bonds, Inter. J. Fracture Mech. 1 (1965) 311. 

Beyer MK, Clausen-Schaumann H. Mechanochemistry the mechanical activation of covalent bonds. Chem Rev 2005 105 2921-2948. 

This chapter dealt with molecular crystals but not with infinitely covalent crystals or polymers, where mechanochemistry (or tribochemistry) occurs upon milling. Covalent bonds are broken in mechanochemistry of crystals and that produces surface plasmas, which can, for example, be used for the mineralization of all organic materials (including TCDD and methane) [109, 110]. An experimentally confirmed prediction is that three-dimensional infinitely covalent crystals (such as Si02, Fe203, glass, ceramics, etc.) are most efficient. Mechanochemical reactions have to be strictly distinguished from pure surface reactions and from solid-state... 

A number of important problems in supramolecular chemistry and mechanochemistry on the single-molecule level, such as the strength of the covalent bond and of intermolecular interactions, and the elasticity of an isolated polymer chain, cannot be addressed by bulk measurements. By solving these problems during the... 

From Sects. 4 to 8 we have summarized the mechanochemistry of polymers of complex topologies. These topological structures are stable and can only be altered by the scission of covalent bonds. In some other cases, the topology of the molecules (or their assembly) is dynamic and flucmates in a stress-free state. In this section, we explore the mechanochemistry of two paradigmatic systems. 

Abstract The past 10 years have seen a resurgence of interest in the field of polymer mechanochemistry. Whilst the destructive effects of mechanical force on polymer chains have been known for decades, it was only recently that researchers tapped into these forces to realize more useful chemical transformations. The current review discusses the strategic incorporation of weak covalent bonds in polymers to create materials with stress-sensing and damage-repairing properties. Firstly, the development of mechanochromism and mechanoluminescence as stress reporters is considered. The second half focuses on the net formation of covalent bonds as a response to mechanical force, via mechanocatalysis and mechanically unmasked chemical reactivity, and concludes with perspectives for the field. 

Recent efforts to report and to repair mechanical damage with mechanochemical reactions form the subject of the current chapter. We start with a brief discussion of the use of the spiropyran unit as a mechanophore for reporting strain. Spiropyran mechanochemistry inspired the development of another stress probe, the highly sensitive mechanoluminescent dioxetane, whose application as scission reporter in several types of polymeric materials is discussed. The chapter continues with a description of recent efforts to develop productive mechanochemistry, where initial scission leads to the formation of new bonds. Bond formation is either induced by the scission of covalent bonds, e.g. by the opening of rings, or bonds are formed under the action of a latent catalyst when it is activated by mechanochemical dissociation of a Lewis acid-base pair. These examples of productive mechanochemistry offer exciting possibilities to develop new modes of self-healing in... 

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