Molecular and electronic structure of dinuclear uranium bis-μ-oxo complexes with diamond core structural motifs.
Schmidt AC, Heinemann FW, Lukens WW, Meyer K (2014)
Publication Status: Published
Publication Type: Journal article
Publication year: 2014
Journal
Book Volume: 136
Pages Range: 11980-11993
Journal Issue: 34
DOI: 10.1021/ja504528n
Abstract
In a multiple-bond metathesis reaction, the triazacyclononane (tacn)-anchored methyl- and neopentyl (nP)-substituted tris(aryloxide) U(III) complex [(((nP,Me)ArO)3tacn)U(III)] (1) reacts with mesityl azide and CO2 to form mesityl isocyanate and the dinuclear bis(μ-oxo)-bridged U(V)/U(V) complex [{(((nP,Me)ArO)3tacn)U(V)}2(μ-O)2] (3). This reaction proceeds via the mononuclear U(V) imido intermediate [(((nP,Me)ArO)3tacn)U(V)(NMes)] (2), which has been synthesized and fully characterized independently. The dimeric U(V) oxo species shows rich redox behavior: complex 3 can be reduced by one and two electrons, respectively, yielding the mixed-valent U(IV)/U(V) bis(μ-oxo) complex [K(crypt)][{(((nP,Me)ArO)3tacn)U(IV/V)}2(μ-O)2] (7) and the U(IV)/U(IV) bis(μ-oxo) complex K2[{(((nP,Me)ArO)3tacn)U(IV)}2(μ-O)2] (6). In addition, complex 3 can be oxidized to provide the mononuclear uranium(VI) oxo complexes [(((nP,Me)ArO)3tacn)U(VI)(O)eq(OTf)ax] (8) and [(((nP,Me)ArO)3tacn)U(VI)(O)eq]SbF6 (9). The unique series of bis(μ-oxo) complexes also shows notable magnetic behavior, which was investigated in detail by UV/vis/NIR and EPR spectroscopy as well as SQUID magnetization studies. In order to understand possible magnetic exchange phenomena, the mononuclear terminal oxo complexes [(((nP,Me)ArO)3tacn)U(V)(O)(O-pyridine)] (4) and [(((nP,Me)ArO)3tacn)U(V)(O)(O-NMe3)] (5) were synthesized and fully characterized. The magnetic study revealed an unusually strong antiferromagnetic exchange coupling between the two U(V) ions in 3. Examination of the (18)O-labeled bis(μ-oxo)-bridged dinuclear complexes 3, 6, and 7 allowed for the first time the unambiguous assignment of the vibrational signature of the [U(μ-O)2U] diamond core structural motif.
Authors with CRIS profile
Anna-Corina Schmidt
Lehrstuhl für Anorganische und Allgemeine Chemie
Frank Wilhelm Heinemann
Lehrstuhl für Anorganische und Allgemeine Chemie
Karsten Meyer
Lehrstuhl für Anorganische und Allgemeine Chemie
Involved external institutions
United States (USA) (US)How to cite
APA:
Schmidt, A.-C., Heinemann, F.W., Lukens, W.W., & Meyer, K. (2014). Molecular and electronic structure of dinuclear uranium bis-μ-oxo complexes with diamond core structural motifs. Journal of the American Chemical Society, 136(34), 11980-11993. https://dx.doi.org/10.1021/ja504528n
MLA:
Schmidt, Anna-Corina, et al. "Molecular and electronic structure of dinuclear uranium bis-μ-oxo complexes with diamond core structural motifs." Journal of the American Chemical Society 136.34 (2014): 11980-11993.
BibTeX: Download