Fe(II) and Fe(III) complexes of N-ethyl-N-phenyl dithiocarbamate: Electrical conductivity studies and Thermal properties

Electrical Properties of Cu-Based Coordination Complexes: Insights from In Situ Impedance Spectroscopy

This study examines the influence of ligand design on the structural, optical, and electrical properties of copper-based coordination complexes. Ligands H2L1 and H2L2 were synthesized via the reaction of 5-nitrosalicylaldehyde with 2-hydroxy- or 4-hydroxybenzhydrazide. H4L3 was obtained from the reaction of carbohydrazide and salicylaldehyde, while H4L4 was prepared by condensing 4-methoxysalicylaldehyde with thiocarbohydrazide. The research focuses on two key design elements: (1) the effect of hydroxyl group positioning on the aroyl ring in hydrazide ligands (H2L1 vs. H2L2) and (2) the impact of carbonyl versus thiocarbonyl groups and aldehyde substituents in hydrazone ligands (H4L3 vs. H4L4). The resulting complexes, [Cu2(L1)2], [Cu2(L2)2(MeOH)3], [Cu2(L3)(H2O)2], and [Cu2(L4)(H2O)2], were synthesized and characterized using attenuated total reflectance infrared (IR-ATR) spectroscopy, thermogravimetric analysis (TG), and UV-Vis diffuse reflectance spectroscopy. Their electrical properties were investigated using solid-state impedance spectroscopy (IS). The crystal and molecular structure of the complex [Cu2(L2)2(MeOH)3]∙MeOH was determined by single-crystal X-ray diffraction (SCXRD). This study underscores the pivotal role of ligand modifications in modulating the functional properties of coordination complexes, offering valuable insights for the advancement of materials chemistry.

An innovative and efficient route to the synthesis of metal-based glycoconjugates: proof-of-concept and potential applications

With a view to developing more efficient strategies to the functionalization of metallodrugs with carbohydrates, we here report on an innovative and efficient synthetic route to generate gold(iii) glycoconjugates in high yields and purity. The method is based on the initial synthesis of the zinc(ii)-dithiocarbamato intermediate [Zn^II(SSC-Inp-GlcN)₂] (Inp = isonipecotic moiety; GlcN = amino-glucose) followed by the transfer of the glucoseisonipecoticdithiocarbamato ligand to the gold(iii) center via transmetallation reaction between the zinc(ii) intermediate and K[Au^IIIBr₄] in 1 : 2 stoichiometric ratio, yielding the corresponding glucose-functionalized gold(iii)-dithiocarbamato derivative [Au^IIIBr₂(SSC-Inp-GlcN)]. No protection/deprotection of the amino-glucose scaffold and no chromatographic purification were needed. The synthetic protocol was optimized for glucose precursors bearing the amino function at either the C² or the C⁶ position, and works in the case of both α and β anomers. The application of the synthetic strategy was also successfully extended to other metal ions of biomedical interest, such as gold(i) and platinum(ii), to obtain [Au^I(SSC-Inp-GlcN)(PPh₃)] and [Pt^II(SSC-Inp-GlcN)₂], respectively. All compounds were fully characterized by elemental analysis, mid- and far-IR, mono- and multidimensional NMR spectroscopy, and, where possible, X-ray crystallography. Results and potential applications are here discussed.

Synthesis, Optical, and Structural Studies of Iron Sulphide Nanoparticles and Iron Sulphide Hydroxyethyl Cellulose Nanocomposites from Bis-(Dithiocarbamato)Iron(II) Single-Source Precursors

In this study, Fe(II) complexes of phenyldithiocarbamate, dimethyldithiocarbamate and imidazolyldithiocarbamate were used as single-source precursors to prepare iron sulphide nanoparticles by thermolysis in oleic acid/octadecylamine (ODA) at 180 °C. The nanoparticles were dispersed into hydroxyethyl cellulose (HEC) to prepare iron sulphide/HEC nanocomposites. Ultraviolet-Visible (UV-Vis), Photoluminescence (PL), Fourier Transform Infrared (FTIR), powder X-ray diffraction (pXRD), high-resolution transmission electron microscopy (HRTEM), Field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS) were used to characterize the iron sulphide nanoparticles and corresponding HEC nanocomposites. The absorption spectra studies revealed that the nanoparticles were blue shifted due to quantum confinement and the optical band gaps of the nanoparticles are 4.85 eV for FeS1, 4.36 eV for FeS2, and 4.77 eV for FeS3. The emission maxima are red-shifted and broader for the nanoparticles prepared from phenyldithiocarbamate. Rod-like and spherically shaped iron sulphide particles were observed from the HRTEM images. The crystallite sizes from the HRTEM images are 23.90-38.89 nm for FeS1, 4.50-10.50 nm for FeS2, and 6.05-6.19 nm for FeS3 iron sulphide nanoparticles, respectively. pXRD diffraction patterns confirmed that FeS1 is in the pyrrhotite-4M crystalline phase, FeS2 is in the pyrrhotite phase, and FeS3 is in the troilite phase of iron sulphide. The phases of the iron sulphide nanoparticles indicate that the nature of the precursor complex affects the obtained crystalline phase. FTIR spectra studies confirmed the incorporation of the nanoparticles in the HEC matrix by the slight shift of the O-H and C-O bonds and the intense peaks on the nanoparticles. FESEM images of the iron sulphide nanoparticles showed flake-like or leaf-like morphologies with some hollow spheres. The EDS confirmed the formation of iron sulphide nanoparticles by showing the peaks of Fe and S.

A Study on Copolymer Systems of Styrene with Diethanolamine Side Group and Methyl Methacrylate

4-Diethanolaminomethyl styrene (DEAMSt) monomer was prepared by the modification of 4-chloromethyl styrene with diethanolamine. The copolymers in different combinations (0.11, 0.19, and 0.30 by mole) of DEAMSt and methyl methacrylate (MMA) were prepared by free radical polymerization method at 60°C in the presence of 1,4-dioxane and AIBN as initiator. The structures of DEAMSt and DEAMSt-MMA copolymer were characterized by FT-IR and 1H-NMR. The glass transition temperature (Tg) of the copolymers was measured by DSC. Thermal decomposition behavior of the copolymers was investigated by TGA. The average molecular weights of the copolymers were determined by GPC. The dye uptaking properties of the copolymers were investigated using bromocresol green. Then, the dielectric constant, dielectric loss factor, and conductivity of copolymers were investigated as a function of temperature and frequency. The activation energies (Ea) of the copolymers were determined by impedance analyzer.

Preparation and Characterization of Styrene Bearing Diethanolamine Side Group, Styrene Copolymer Systems, and Their Metal Complexes

The two copolymer systems of styrene bearing diethanol amine side group and styrene were prepared by free radical polymerization method at 60°C in presence of 1,4-dioxane as solvent and AIBN as initiator. Their metal complexes were prepared by reaction of the copolymer used as ligand P(DEAMSt-co-St)L′′ and Ni(II) and Co(II) metal ions, which was carried out in presence of ethanol and NaOH at 65°C for 48 h in pH = 7.5. The structures of the copolymers used as ligand and metal complexes were identified by FT-IR, 1H-NMR spectra, and elemental analysis. The properties of the copolymers used as ligand and metal complexes were characterized by SEM-EDX, AAS, DSC, TGA, and DTA techniques. Then, the electrical properties of the copolymers and metal complexes were examined as a function of the temperature and frequency, and the activation energies (Ea) were estimated with conductivity measurements.