Thermodynamic properties of o-semiquinonato complexes of cobalt, nickel, and copper in the range T → 0 to 350 K

The heat capacity of bis(3,6-di-tert-butyl-o-benzosemiquinonato)copper, (triethylarsine)bis(3,6-di-tert-butyl-o-benzosemiquinonato)nickel, and (triphenylphosphine)bis(3,6-di-tert-butyl-o-benzosemiquinonato)cobalt was determined in the range of 0 to 350 K by precision adiabatic vacuum calorimetry. The temperature dependences of magnetic moments were studied for the last two complexes. The G-transition in nickel complex, which is presumably caused by a loosening of the molecular degrees of freedom, was determined. The standard thermodynamic functions of complexes were calculated according to the obtained data: C ○ , H○(T)-H○(0), S○(T), and G○(T)-H○(0) for the range of T → 0 to 350 K. It was concluded that our analysis of low-temperature heat capacity based on the Debye theory of the heat capacity of solids and the multifractal model confirms the chain-layer topologies of the structures of the investigated complexes.