Structural, optical, electrical conductivity, and thermal properties of some mononuclear and mixed metal complexes of diethyldithiocarbamate
摘要
This study aims to synthesize and characterize a series of mononuclear and mixed metal diethyldithiocarbamate complexes containing Ag(I), Cu(II), Mn(II), and selenium ions, and to explore their structural, optical, electrical, and thermal properties. These complexes are of considerable interest because metal dithiocarbamates can serve as versatile single-source precursors for the fabrication of semiconductor materials and other advanced functional systems. The synthesized complexes were characterized using XRD, elemental analysis (SEM–EDX), spectroscopy techniques (IR, NMR, UV–Vis, ESR, and fluorescence), magnetic measurements, density functional theory (DFT), and thermal analyses (TGA, DTA, DSC). Structural investigations confirmed the ability of diethyldithiocarbamate ligands to form multinuclear coordination assemblies with the investigated metal ions, producing sponge-like structures. The UV–visible spectra showed strong absorption at 240–435 nm and high transmission (84%-99%) around 300 nm, with an optical band gap between 1.95 and 4.15 eV. The oscillator and the dispersion energies of linear refractive index (n) were evaluated using the Wemple Di-Domenico single oscillator model. The emission spectra exhibited three fluorescence peaks in the range 427–531 nm. The dielectric characteristics and alternating current conductivity (σω) were measured at temperatures ranging from 298 to 400 K and frequencies between 120 Hz and 100 kHz. The electrical measurements of the samples revealed semiconducting behavior with σω values of 10–7–10–1 S/m, and Ea of 0.035–2.71 eV. Various conduction mechanisms were observed with increasing temperature, as evidenced by changes in the dielectric parameters. Thermal analyses emphasized that complexes may be applied for the synthesis of nanoscale metal sulfides with semiconductor properties.