| Popis: |
Adaptability to various and frequent environmental stresses, such as temperature or pressure deviations, is one of the key features for the survival of living beings. As the development of new materials tends to recreate the perfect functioning principles of the biological systems’ machinery, the compliance of a material is found to be one of the crucial characteristics that needs to be achieved. The requirement of materials' dynamic behaviour was regularly a limiting factor in considering crystals as a potential materials of choice. Relatively recent serendipitous discovery of the crystals which are capable of adapting to outer (mechanical) stimulus with plastic or elastic deformation, whilst concurrently retaining other properties such as optical or electrical conductivity, firmly paved the way to their potential utilization in the development of advanced smart devices. However, the intricacy of structural features, which allow mechanically induced deformation of crystals, especially of metal-organic compounds, is still not resolved, and a detailed structure–mechanical property correlation is needed. For that purpose, crystalline one-dimensional coordination polymers were found to be the perfect model system for a methodical study of mechanically induced flexibility, as even amongst the limited number of reported cases an unexpectedly wide range of mechanical responses can be observed, which materialized as a consequence of introducing subtle structure changes. The continuation of the research on this class of compounds showed that coordination polymers of cadmium(II) and copper(II) halides with 3, 5-dimethylpyrazine ligands provide an avenue of a diverse mechanical responses. Adaptability of the crystals was thoroughly investigated through a variety of custom-made mechanical experiments and impact of introducing controlled structural modifications on the mechanical output was monitored. Special attention has been paid to the influence of the metal centre exchange on the structural features, especially on the intermolecular interactions that emerged as one as one of the main structural parameters responsible for targeting the specific mechanical response. |
