Thiuram disulfide intercalated hybrid materials of layered lead and cadmium iodides

Thiuram disulfide intercalates of lead(II) and cadmium(II) were prepared by the reaction of binary layered metal iodides with five dithiocarbamates in air. The intercalates were characterized by elemental analysis, Powder X-ray diffraction (XRD), infrared (IR), ultraviolet–visible spectroscopy, diffuse reflectance spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM) techniques. IR showed increased contribution of the thioureide bond and the presence of weak disulfide stretching frequency. Powder XRD showed the characteristic intermediate 2θ signal confirming the intercalation. Powder XRD clearly differentiated intercalates from the iodinated product of dithiocarbamate. As the bulkiness of substituents on disulfide increased, “d” also increased. The higher thermal stability associated with intercalates clearly suggests a strong ionic interaction and a difficult de-intercalation. SEM images of lead intercalates indicated crystalline nature. The intercalates appeared as rods or spheres. The diallyl-intercalate, [PbI₂](H₅C₃)₂NCSS-SSCN(C₃H₅)₂ (where (H₅C₃)₂NCSS-SSCN(C₃H₅)₂ is diallylthiuram disulfide), shows “net like structures.” Intercalation of oxidized dithiocarbamates in the “galleries” of layered PbI₂/CdI₂ is observed. HRTEM and AFM analysis of intercalates showed the particles to be nano-rods.