Investigations in the Field of Carbene-Boron Chemistry

Diploma Thesis from the year 2003 in the subject Chemistry - Anorganic Chemistry, grade: 1,0, Technical University of Braunschweig (Institut für Anorganische und Analytische Chemie), course: TU Braunschweig und University of Alabama, 45 entries in the bibliography, language: English, comment: Der experimentelle Teil dieser Arbeit wurde in der Arbeitsgruppe von Anthony J Arnduengo III an der University of Alabama durchgeführt. Es werden die klassischen Methoden zur Synthese von Singulett-Carbenen beschrieben, sowie Versuche zu Anlagerung von Borverbindungen. Die dabei entdeckten Imidazolium-Borhydride wurden auf Tauglichkeit als Speicherverbindung für molekularen Wasserstoff hin untersucht. , abstract: From a long time ago attempts have been made to isolate carbenes. A big motivation behind the search for a stable carbene was the fact, that oxidation state II is well known for the late members of group 14, germanium, tin and lead. Therefore it should be possible to produce a compound containing a carbon in oxidation state II, which is stable enough to be detected and possibly isolated and characterized. Additionally carbenes may be useful as building blocks in organic syntheses. They form complexes with a wide variety of main group elements and transition metals in both high and low oxidiation states. Many of these complexes are highly efficient homogeneous catalysts. Carbenes are defined as compounds possessing a divalent carbon in their structure. This carbon is bound to two adjacent groups by covalent bonds. It has two nonbonding electrons which may have parallel (singlet state) or antiparallel spins (triplet state). The simplest example of a carbene is methylene. The area of carbene boron chemistry is a relatively new area of research. Like most other fields of carbene research it has been revived by the discovery of stable carbenes by Arduengo in 1991. Until then only a few neutral borane adducts with electroneutral carbon bases were known. Most carbon bases