Synthesis of novel homoleptic and heteroleptic transition metal carbonyl and nitrosyl cations

Abstract: The aim of this thesis was the synthesis of novel and unprecedented transition metal cations, stabilized by weakly coordinating anions (WCAs). For that, the 3d transition metals Cr, Mn, Fe and the group VI triad Cr, Mo and W were examined in combination with the gas molecules carbon monoxide (CO) and nitrogen monoxide (NO) as ligands. The obtained complexes of the general type [M(CO)x(NO)y][WCA] (x = 0–6, y = 4–0; M: Cr, Mo, W, Mn, Fe; WCA = [Al(ORF)4]–, [F-Al(ORF)3}2]–) were fully characterized by vibrational spectroscopy, NMR or EPR spectroscopy as well as single-crystal and powder X-ray diffraction. The obtained data were supported and validated by quantum mechanical calculations.
Homoleptic transition metal carbonyl complexes have been known for over 130 years. Nowadays, this family of compounds has many representatives, which often were thoroughly analyzed due to their rich follow-up, redox or substitution chemistry. However, homoleptic carbonyl cations are considerably underrepresented due to their intrinsically high reactivity. Therefore, radical or cluster species were hitherto completely unknown. In this work, the first synthesis and full characterization of the homologous transition metal carbonyl radical cations [Cr/Mo/W(CO)6]+ was achieved.
Homoleptic transition metal nitrosyl complexes are in general much scarcer than their carbonyl analogs. Just one example each of anionic and neutral homoleptic representatives has been isolated and characterized yet and cations were unknown altogether. Over the course of this thesis, the first homoleptic transition metal nitrosyl cation [Mn(NO)4]+ was synthesized as a WCA salt and thoroughly characterized and analyzed. Especially concerning the complex bonding situation of NO complexes, novel insights could be gained.
Heteroleptic, mixed, carbonyl/nitrosyl cations were, comparable to their homoleptic brethren, similarly unexplored: only one single complex of this species has been observed as of yet. As a part of this thesis, the WCA salts of the novel cations [Cr/Mo/W(CO)5(NO)]+, [Fe(CO)4(NO)]+ and [Fe(CO)(NO)3]+ were synthesized and fully characterized

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Notes: Universität Freiburg, Dissertation, 2020

Classification and Topics

• Keyword: Cations ; Metallorganische Verbindungen ; Präparative anorganische Chemie

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2020
• Creator: Bohnenberger, Jan
• Contributor: Krossing, Ingo ; Albert-Ludwigs-Universität Freiburg. Fakultät für Chemie und Pharmazie

Further information

• DOI: 10.6094/UNIFR/165642
• URN: urn:nbn:de:bsz:25-freidok-1656428
• Rights: Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:52 PM CET