In this thesis, the feasibility of employing organometallic single-source precursors in the preparation of advanced transition metal pnictide materials such as colloidal nanoparticles and films has been investigated. In particular, the ternary FeMnP phase was targeted as a model for preparing advanced heterobimetallic phosphide materials, and the iron-rich Fe 3 P phase was targeted due to its favorable ferromagnetic properties as well as the fact that the preparation of advanced Fe 3 P materials has been elusive by commonly used methods. Progress towards the synthesis of advanced Fe 2-x Mn x P nanomaterials and films was facilitated by the synthesis of the novel heterobimetallic complexes FeMn(CO) 8 (μ-PR 1 R 2 ) (R 1 = H, R 2 = H or R 1 = H, R 2 = Ph), which contain the relatively rare μ-PH2 and μ-PPhH functionalities. Iron rich Fe 2-x Mn x P nanoparticles were obtained by thermal decomposition of FeMn(CO) 8 (μ-PH 2 ) using solution-based synthetic methods, and empirical evidence suggested that oleic acid was responsible for manganese depletion. Films containing Fe, Mn, and P with the desired stoichiometric ratio of 1:1:1 were prepared using FeMn(CO) 8 (μ-PH 2 ) in a simple low-pressure metal-organic chemical vapor deposition (MOCVD) apparatus. Although the elemental composition of the precursor was conserved in the deposited film material, spectroscopic evidence indicated that the films were not composed of pure-phase FeMnP, but were actually mixtures of crystalline FeMnP and amorphous FeP and Mn x O y . A new method for the preparation of phase-pure ferromagnetic Fe 3 P films on quartz substrates has also been developed. This approach involved the thermal decomposition of the single-source precursors H 2 Fe 3 (CO) 9 PR (R = t Bu or Ph) at 400 °C. The films were deposited using a simple home-built MOCVD apparatus and were characterized using a variety of analytical methods. The films exhibited excellent phase purity, as evidenced by X-ray diffraction, X-ray photoelectron spectroscopy, and field-dependent magnetization measurements, the results of which were all in good agreement with measurements obtained from bulk Fe 3 P. As-deposited Fe 3 P films were found to be amorphous, and little or no magnetic hysteresis was observed in plots of magnetization versus applied field. Annealing the Fe 3 P films at 550 °C resulted in improved crystallinity as well as the observation of magnetic hysteresis.

The thesis presented here is focused on the synthesis of iron-bismuth alkoxides and siloxides as precursors for multiferroic BiFeO₃ systems. Spectrum of novel cyclopentadienyl substituted iron-bismuth complexes of the general type [{Cp^y(CO)₂Fe}BiX₂], as potential precursors for cyclopentadienyl iron-bismuth alkoxides or siloxides [{Cp^y(CO)₂Fe}Bi(OR)₂] (R-O^tBu, OSiMe₂^tBu), were obtained and characterised. The use of wide range of cyclopentadienyl rings in the iron carbonyl compounds allowed for a comprehensive analysis of its influence on structure, reactivity as well as solubility of the studied complexes, which are crucial features of potential precursors. The results fill the gap in the chemistry of cyclopentadienyl iron-bismuth complexes. In this work a new method of preparation of novel alkoxides or siloxides iron-bismuth complexes has been developed. In the reaction of Fe₂(CO)₉ with Bi(O^tBu)₃ or Bi(OSiMe₂^tBu)₃ molecular precursors for preparation of heterobimetallic oxides were obtained. Moreover, characterised compounds allowed to extend the knowledge about existence of iron-bismuth clusters and open new ways for the further investigations on the carbonyl iron-bismuth siloxides and alkoxides. The resulting compounds are good single source precursors for the BiFeO₃ materials. The presented synthetic route can be generalized and other heterobimetallic compounds can be obtained. This work should also be helpful in the designing new precursors for synthesis of metal oxides.

Dans ce manuscrit, un travail multidisciplinaire, de la synthèse de précurseurs métalliques à la caractérisation des matériaux est présenté. La première porte sur l’élaboration de poudres d’oxyde TiO2 dopé Nb5+ et d’oxydes mixtes SnO2-TiO2 dopé Nb5+ par une approche Sol-Gel. Leur mise en forme sous forme de pastille par une méthode moderne de frittage flash (SPS) a permis d’étudier leurs propriétés physiques vibrationnelles et thermoélectriques. La deuxième partie de cette étude présente l’élaboration de nouveaux précurseurs d’étain et de tantale adaptés au procédé de dépôt de couches minces par DLI-MOCVD. Afin de répondre aux exigences de ce procédé, des dérivés moléculaires à base de ligand beta-aminoalcool fluoré ou pas ont été élaborées. Les complexes métalliques ont ensuite été entièrement caractérisés à l’état solide et en solution. Le bon comportement thermique (stabilité et volatilité) de certains de ces composés ont conduit à l’élaboration et à la caractérisation de couches minces de SnO2 et SnO2:F / In this manuscript, a multidisciplinary work, from the synthesis of metal precursors to the characterization of materials, is presented. The first concerns the development of Nb5+ doped TiO2 oxide powders and Nb5+ doped SnO2-TiO2 mixed oxides by a Sol-Gel approach. Their shaping into a pellet form by a modern flash sintering method (SPS) made it possible to study their physical, vibrational and thermoelectric properties. The second part of this study presents the development of new tin and tantalum precursors adapted to the DLI-MOCVD thin film deposition process. In order to meet the requirements of this process, molecular derivatives based on fluorinated or non-fluorinated beta-aminoalcohol ligand have been developed. The metal complexes were then fully characterized in solid state and in solution. The good thermal behaviour (stability and volatility) of some of these compounds has led to the development and characterization of thin layers of SnO2 and SnO2:F

The thesis presented here is focused on the synthesis of iron-bismuth alkoxides and siloxides as precursors for multiferroic BiFeO₃ systems. Spectrum of novel cyclopentadienyl substituted iron-bismuth complexes of the general type [{Cp^y(CO)₂Fe}BiX₂], as potential precursors for cyclopentadienyl iron-bismuth alkoxides or siloxides [{Cp^y(CO)₂Fe}Bi(OR)₂] (R-O^tBu, OSiMe₂^tBu), were obtained and characterised. The use of wide range of cyclopentadienyl rings in the iron carbonyl compounds allowed for a comprehensive analysis of its influence on structure, reactivity as well as solubility of the studied complexes, which are crucial features of potential precursors. The results fill the gap in the chemistry of cyclopentadienyl iron-bismuth complexes. In this work a new method of preparation of novel alkoxides or siloxides iron-bismuth complexes has been developed. In the reaction of Fe₂(CO)₉ with Bi(O^tBu)₃ or Bi(OSiMe₂^tBu)₃ molecular precursors for preparation of heterobimetallic oxides were obtained. Moreover, characterised compounds allowed to extend the knowledge about existence of iron-bismuth clusters and open new ways for the further investigations on the carbonyl iron-bismuth siloxides and alkoxides. The resulting compounds are good single source precursors for the BiFeO₃ materials. The presented synthetic route can be generalized and other heterobimetallic compounds can be obtained. This work should also be helpful in the designing new precursors for synthesis of metal oxides.