Sonochemical synthesis of cadmium (II) Schiff base complex and its decomposition to CdO nanoparticles

Cadmium complexes have an important role in many areas of researches such as supramolecular, biological and luminescence advices.1-4 Among synthesized d10 transition metal complexes (Zn(II), Cd(II), Cu(I), Ag(I) and Au(I)) with luminescent properties,5-6 cadmium (II) has an advantage because of its coordination number is usually different from the other d10 transition metals. Th e coordination number of Cd(II) lies between 6 and 8 while for Zn(II), Ah(I), Au(I) and Cu(I) the coordination number usually lies between 4-6. Th e greater coordination number of Cd(II) cause unique structures and various structure-related properties.3 CdO is an important n-type semiconductor with a cubic structure, which belongs to the II–VI group. Th e direct and indirect band gap energy of this semiconductor is 2.2-2.7 eV and 1.36-1.98 eV respectively.7 Th e difference in band gap is ascribed by natural cadmium and oxygen vacancies. CdO has noticeable properties such as wide band gap, low electrical resistivity and high transmission in the visible region. Because of its distinguished properties cadmium oxide is widely used as a transparent conductive oxide (TCO) in optoelectronic devices, specifically in solar cells,8 photo transistors,9 liquid crystal display, diodes, transparent electrodes, and gas sensors.10 In this study, solvothermal method was described for synthesis of a new cadmium(II) complex of [Cd(EtOH)(HL)(NO3)]2(1), (H2L = 2-[(2-Hydroxy-propylimino)-methyl]-6-methoxy-phenol). Th e compound 1 in nano-size was used as an initial reagent to gain nanoparticles of cadmium(II) oxide with thermal decomposition.