Structure and optical properties of glasses in binary liquid crystalline systems based on cobalt octanoate

•Glassy liquid crystalline systems based on cobalt (II) octanoate.•Optical properties and structure were studied.•Bilayer and nanoporous structure of glasses depends on the polarizing power of metal cations.•Several coordination forms of Co (II) ions coexist in the systems.

The effect of composition and aggregative state (melt, mesophase, glass) on the coordination state of Co (II) ions in an octanoate ligand field has been studied for binary liquid crystalline systems based on cobalt (II) octanoate by the analysis of electronic absorption spectra. It has been shown that several coordination forms of Co (II) ions: octahedral, tetrahedral and dodecahedral ones can coexist in cobalt octanoate based systems. It has been found by positron annihilation lifetime spectroscopy and small-angle X-ray scattering that glasses of cobalt octanoate based systems have a bilayer and nanoporous structure. The thickness of cation–anion bilayers in mesophases and glasses of binary systems depends on the polarizing power of cations: it is the smaller, the higher the polarizing power of cations.