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With the aim of finding alternative reaction media for the synthesis of subvalent main group and transition metal cluster compounds, traditionally made through solid state reactions or in superacidic media, different alternative reaction media have been explored in this work. Room-temperature ionic liquids are amongst the more unconventional reaction media used. The syntheses performed have been aimed at both anionic and cationic cluster and the main tools used for characterization have been different X-ray diffraction and spectroscopic techniques.

Selected ionic liquids have along with dichloromethane been shown to work as alternative reaction media for room temperature synthesis of the Bi₅[GaCl₄]₃ salt. The salt containing the subvalent naked bismuth polycation Bi₅³⁺ was isolated from reduction reactions of BiCl₃ in Ga/GaCl₃-dichloromethane respectively Ga/GaCl₃-ioinc liquid media. Three different classes of ionic liquids based on phosphonium-, imidazolium- and pyrrolidinium- salts have been used in synthesis. Homopolyatomic clusters from the lighter Group 15 element arsenic have also been studied. Solutions from the oxidative and reductive reaction routes of arsenic and AsCl₃ in Lewis acidic toluene media were studied by EXAFS spectroscopy. The results were evaluated using molecular dynamics simulations of arsenic clusters. A discussion on how the calculated As4 cluster model relates to the experimental data resulted from this study.

In terms of homopolyatomic anionic clusters the [K⁺(2,2,2-crypt)]₂Ge₉^2- compound containing the naked Ge₉^2- anionic cluster has been isolated. The crystallographic investigation of [K⁺(2,2,2-crypt)]₂Ge₉^2- shows Zintl cluster anion Ge₉^2- to be tricapped trigonal-prismatic with a symmetry very close to D_3h. A chemical bonding analysis reveals two local minima of D_3h symmetry and the cluster interaction scheme to be based on highly delocalised bonding.

Ligand supported transition metal clusters from tungsten and palladium have also been prepared. Reduction of WCl₆ in a reaction mixture of ionic liquid and co-solvent toluene resulted in tritungsten decachloride; W₃Cl₁₀(MeCN)₃, being formed. Furthermore, palladium sandwich compounds; [Pd₂(Ga₂Cl₇)(C₇H₈)₂], [Pd₂(GaCl₄)(C₉H₁₂)₂]∙C₉H₁₂ and [Pd₂(Ga₂Cl₇)(C₆H₅Cl)₂] have been prepared using GaCl₃-arene reaction media.