engleski

Mechanically Adaptable Crystals: Impact of Supramolecular Connectivity on Crystal Flexibility

There is a constant need for specific devices with improved performances, what in turn requires simultaneous development of new configurable materials. Materials that display dynamic characteristics similar to those of living beings, i.e. having the ability to change shape or move, along with fast and efficient energy transfer, are highly desired and among the top targeted ones in current materials design. Recently, it has been found that some crystalline materials are capable of responding mechanically to the application of a variety of external stimuli, such as light, thermal energy or mechanical pressure, what makes them excellent candidates for usage in the design of new smart devices. So far, a number of organic crystals that respond flexibly upon the application of mechanical force have been reported, but only two reports on elastically bendable metal-organic compounds could be found in the literature. Since the insertion of a metal centre in organic systems opens a whole new spectrum of possible applications, we decided to systematically explore metal-organic systems with the aim to fully understand the structural features that endue the metal-organic crystals with mechanical flexibility. For that purpose several coordination polymers of cadmium(II) halides with pyrazine based ligands were synthesized, and the adaptability of those crystals to external mechanical stress was tested. For crystals that displayed elastic behaviour, the responses were quantified and correlated with structural features, primarily the strength and geometry of supramolecular interactions, but also with the mechanical behaviour of analogous metal- containing systems.

coordination polymers ; cadmium(II) ; flexible crystals

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