- Title
- Ruthenium sulphide nanoparticles derived from tri-dithiocarbamato ruthenium (III) complexes : synthesis, optical and structural studies
- Creator
- Mbese, Johannes Zanoxolo
- Subject
- Nanoparticles Ruthenium compounds
- Date
- 2017
- Type
- Thesis
- Type
- Doctoral
- Type
- DPhil
- Identifier
- http://hdl.handle.net/10353/15420
- Identifier
- vital:40406
- Description
- The present Thesis pioneer the application of single-source molecular precursor method for the synthesis of ruthenium sulfide nanoparticles using a series of novel self-prepared single-source molecular precursors. The preparation of precursors involved the design and synthesis of compounds containing all the desired elements required within the coordination compound. Good precursors are tailored to give reproducible, clean decomposition at moderate temperatures, leading to high quality, defect free, mono-dispersed nanoparticles. Nine (9) homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared from a stoichiometric reaction of RuCl3·H2O with self-prepared dithiocarbamate ligands at room temperature in a molar ratio of Ru3+: Ligand of 1:3. Dithiocarbamate ligands were derived from a stoichiometric reaction of carbon disulfide with (aniline, N-allylmethylamine, p-toluidine, p-anisidine, N-ethyl-m-toluidine, piperidine, morpholine, di-isopropylamine, and diallylamine) in the presence of concentrated ammonia or potassium hydroxide in ice cold bath. The dithiocarbamate ligands and complexes were characterized by elemental analyses, UV-Vis, Fourier transform infrared spectroscopy (FTIR), 1H- and 13C-NMR spectroscopy. Thermogravimetric analyses (TGA) was used to study the decomposition profiles of the precursor complexes. The results obtained from the TGA of precursors showed that the complexes decompose to ruthenium sulfide nanoparticles. The FTIR spectra of the ligands revealed prominent strong absorption bands ascribed to v(N-H) stretching vibrations and also confirm the bidentate coordination of the dithiocarbamate ligands. Ruthenium(III) complexes show absorption spectra in the visible region that exhibit bands attributed to n → π* electronic transitions located on the sulfur atoms located in the S–C–S and N–C–S chromophores of the bidentate dithiocarbamate ligands respectively. The absorption spectra also confirmed the geometry of ruthenium(III) complexes to be octahedral. The proposed structures of dithiocarbamate ligands and ruthenium(III) complexes were confirmed by the 1H- and 13C-NMR. The complexes were used as single-source molecular precursors for the synthesis of ruthenium sulfide nanoparticles. The structural and optical properties were studied using transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis absorption and photoluminescence (PL) spectra. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the –NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. The XRD confirmed the successful formation of Ru2S3 nanoparticles induced by the thermal decomposition of series of [Ru(S2CNR2)3] complexes. The diffraction peaks: 2θ = 29.43, 40.54, 49.33, 51.86, 61.92, and 75.94 were assign the Miler indices (hkl) to be (111), (211), (220), (300), (222) and (330) reflections, respectively, and were found to be in agreement with a cubic crystal structure reported in database file of (JCPDS 19-1107). The particle sizes estimated from Scherer's equation were found in a range between 2.5 and 4.9 nm. EDS spectra reveal that the prepared nanoparticles are mainly composed of Ru and S, confirming the presence of Ru2S3 nanoparticles in cubic phase. The inner morphology of nanoparticles was obtained by transmission electron microscopy (TEM) and most nanoparticles had narrow particle size distribution characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot was found in the range (3.44 to 4.18 eV) values.
- Format
- 200 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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UFH Department of Chemistry
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| View Details | SOURCE1 | PhD (Chemistry) MBESE, JZ.pdf | 7 MB | Adobe Acrobat PDF | View Details |