Thermal, dielectrical properties and conduction mechanism of Cu(II) complexes of azo rhodanine derivatives

•Cu(II) complexes of azo rhodanine derivatives were prepared and characterized.•The variation of substituent affects the thermal properties and dielectric properties of complexes.•Ac conductivity is investigated in the frequency range 0.1–100 kHz and temperature range 303–600 K.•Correlated barrier hopping and small polarons tunneling are the dominant conduction mechanisms.•The values of the thermal activation energies of electrical conductivity were calculated.

A novel series of Cu(II) complexes of azo rhodanine derivatives [CuLn(OAc)(OH2)]2H2O (n = 1, R = OCH3; n = 2, CH3; n = 3, H; and n = 4, NO2) have been synthesized. The alternating current conductivity (σac) and dielectric properties of Cu(II) complexes of azo rhodanine derivatives were investigated in the frequency range 0.1–100 kHz and temperature range 303–600 K. The values of the thermal activation energies of electrical conductivity ΔE1 and ΔE2 for all Cu(II) complexes [CuLn(OAc)(OH2)]2H2O were calculated at different frequencies. The conductivity depends on the substituents of the complexes. The correlated barrier hopping (CBH) is the dominant conduction mechanism for complexes [CuLn(OAc)(OH2)]2H2O (n = 1, 2 and 4) while for complex [CuL3(OAc)(OH2)]2H2O the small polarons tunneling (SPT) is the dominant conduction mechanism.

Graphical abstractThe relation between frequency exponent, S, versus temperature, T, for Cu(II) complexes (1–4).Figure optionsDownload full-size imageDownload as PowerPoint slide