The Effect of Oxidation State and Tert-Butyl Substituents on the Thermal Behavior and Thin-Film Morphology of Cobalt-Complexes (FK 102 and FK 209)

•Thermodynamic and morphological studies are reported for cobalt complexes/TFSI salts.•Thermal properties and thin-film morphology of FK 102 and FK 209 complexes are presented.•The metal oxidation state and the tert-butyl groups have a strong impact on the thermal and morphological behavior.•Compact nanofilms are formed when the metal complexes comprise tert-butyl groups.•A relatively unhindered rotation of the tert-butyl groups in the crystalline phase is observed.