Seredyuk M. Phase and spin transitions in iron(II) coordination compounds

The dissertation is devoted to synthesis, structural studies and properties of iron(II) metallomesogens. 17 Mononuclear and 12 one-dimensional polymeric coordination compounds have been synthesized and characterized. Precursors and the complexes have been studied by a series of spectroscopic, structural and magnetic methods. It has been found that melting of mononuclear alkyl derivatives leads to the formation of smectic mesophases. The detailed analysis of structural data points out thinning of ionic layers upon melting, that causes appearance of the spin transition with hysteresis inside the mesophase. Metallomesogens based on 1D coordination polymers exhibit discotic columnar hexagonal mesophase and vitrify upon cooling with retardation of the spin transition. According to the type of the interaction between phase and spin transitions a classification of spin crossover metallomesogens has been proposed, which includes three main types: (а) with interaction; (b) with co-existence without interaction and (c) without interaction. It has been shown a possibility to utilize the obtained alkylated complexes as thermochromic markers for banknotes, displays and memory elements.