Synthesis of Cyclobutadienecobalt Derivatives and Their Phase Transition Behavior

Abstract

Thermal phase transition behavior of cyclobutadienecobalt derivatives having long alkoxy lateral groups which we prepared recently was re-investigated in detail by the optical measurement using the crossed polarizers and different scanning calorimetry (DSC). These cyclobutadienecobalt derivatives were found to reveal the solid polymorphism: two types of crystals K_1 and K_2 (crystals with lower and higher m.p., respectively) were observed. The melting points of both K_1 and K_2 became lower as the number of the carbon atoms in the alkoxy chain increased.