engleski

Crystalline coordination polymers with flexible response to applied external mechanical force

Crystals have for a long been perceived as static, stiff and brittle, and most of all, stationary objects. In addition to a growing number of reports that contradict this traditional way of appreciating crystalline matter where crystals have been found to move, jump, flex or even explode as a response to a number of external stimuli other than mechanical force, mechanical flexibility has recently appeared as a new and highly important addition to this platform. It has so far been observed for only a bunch of organic crystals and a sole single 0‐D metal complex. Recently, we have reported on a class of crystalline coordination polymers of cadmium(II) capable of displaying exceptional mechanical elasticity in response to application of external pressure. The structural 1‐D spine was decorated with small and rigid heterocyclic ligands bearing halogen functionality adjacent to the heterocyclic nitrogen atom thus forming a supramolecular functionality capable of forming both hydrogen and halogen bonds. It has been shown that slight differences in strengths and geometry of the intermolecular interactions, in a combination with substantial structural interlocking that is orthogonal to the direction of crystal elongation, are critical for inducing and controlling the highly unusual mechanical responses of crystalline metal‐based polymeric materials. To fully understand all the structural features necessary for imparting mechanical flexibility to crystalline materials, and thus ensuring their categorization as a promising new class of smart materials, we are reporting on a different family of crystalline coordination polymers with substantial flexible properties.

crystal engineering, supramoleuclar interactions, flexible crystals

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