ソフトマテリアルとしての金属錯体の機能開拓

抄録

　Flexible and soft molecules are at the focus of materials research for the construction of functional devices for polymer, LB film, gel, liquid crystal and a number of biological materials. These flexible and soft metal complexes can easily be produced by adding long alkyl chains to their periphery. The soft metal complexes are very interesting from the point of view not only of functional materials, but also for phase transitions involving a synchronicity between the central metal complex and the long alkyl chains. Spin-crossover (SCO) compounds exhibiting conversion between high-spin (HS) and low-spin (LS) states are phase transition compounds, and the SCO phenomenon is very often found in iron(II), iron(III), and cobalt(II) compounds. In the solid state, The cooperativity is considered if intermolecular interactions are sufficiently strong. The cooperativity induces abrupt spin transitions and hysteresis loops in SCO compounds, which is the reason why the role of intermolecular interactions in spin transitions has been extensively studied. In the present review, we focus our attention on the flexible and soft SCO iron(II), iron(III) and cobalt(II) compounds with long alkyl chains. The flexible and soft SCO molecules can produce soft materials, i.e. LB films, liquid crystals, self-assembled molecules. Here we attempt to illustrate the topics about multi-functional SCO compounds with long alkyl chains.