Subvalent Cluster Compounds and Synthesis in Alternative Reaction Media
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
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 Bi5 3+ 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 D3h. A chemical bonding analysis reveals two local minima of D3h 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.
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. , vi, 72 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2012:64
metal cluster, Zintl ion, metal-organic 'sandwich' complex, ionic liquid, X-ray diffraction, spectroscopy, crystal structure
IdentifiersURN: urn:nbn:se:kth:diva-107218ISBN: 978-91-7501-579-8OAI: oai:DiVA.org:kth-107218DiVA: diva2:575637
2012-12-20, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Johnsson, Mats, Professor
Kloo, Lars, Professor
FunderSwedish Research Council, B61416
QC 201212122012-12-122012-12-102012-12-12Bibliographically approved
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