TY  - JOUR
A1  - Paprocki, Valerie
A1  - Hrobárik, Peter
A1  - Harriman, Katie L. M.
A1  - Luff, Martin S.
A1  - Kupfer, Thomas
A1  - Kaupp, Martin
A1  - Murugesu, Muralee
A1  - Braunschweig, Holger
T1  - Ein neutrales 1,4‐Diborabenzol als \(\pi\)‐Ligand in Actinoidkomplexen
JF  - Angewandte Chemie
N2  - Die \(\pi\)-Koordination von Aren- und anionischen Heteroarenliganden ist ein allgegenwärtiges Strukturmotiv in der metallorganischen Chemie der d- und f-Block-Elemente. Im Gegensatz dazu sind vergleichbare \(\pi\)-Wechselwirkungen neutraler Heteroarene, darunter auch solche neutraler, aromatischer Borheterocyclen, für den f-Block weit weniger verbreitet, was z. T. mit einer geringeren Effektivität der Metall-zu-Ligand-Rückbindung in Zusammenhang gebracht werden kann. Für die Actinoide sind π-Komplexe mit neutralen Heteroarenliganden sogar gänzlich unbekannt. Durch Ausnutzung der außergewöhnlichen \(\pi\)-Donorstärke eines 1,4-Diborabenzols ist es uns nun gelungen, eine Reihe stabiler π-Halbsandwichkomplexe des Thoriums(IV) und des Urans(IV) über einen erstaunlich einfachen Zugang zu generieren: Umsetzung eines 1,4-Diborabenzols mit ThCl\(_{4}\)(dme)\(_{2}\) bzw. UCl\(_{4}\) in Gegenwart einer Lewis-Base. Hierdurch konnten die ersten Beispiele für Actinoidkomplexe mit einem neutralen Borheterocyclus als Sandwich-artigem Liganden erhalten werden. Laut experimentellen und theoretischen Studien ist die starke Actinoid-Heteroaren-Wechselwirkung in diesen Molekülen im Wesentlichen von elektrostatischer Natur. Der kovalente Hauptbeitrag wird hingegen von der Ligand-zu-Metall-\(\pi\)-Wechselwirkung geleistet, während \(\pi\)/δ-Rückbindungsanteile kaum eine Rolle spielen.
KW  - Actinoide
KW  - Bindungsverhältnisse
KW  - Bor
KW  - Heterocyclen
KW  - \(\pi\)-Komplexe
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218181
VL  - 132
IS  - 31
SP  - 13209
EP  - 13216
ER  - 
TY  - JOUR
A1  - Tendera, Lukas
A1  - Luff, Martin S.
A1  - Krummenacher, Ivo
A1  - Radius, Udo
T1  - Cationic Nickel d\(^{9}\)‐Metalloradicals [Ni(NHC)\(_{2}\)]\(^{+}\)
JF  - European Journal of Inorganic Chemistry
N2  - A series of five new homoleptic, linear nickel d\(^{9}\)‐complexes of the type [Ni\(^{I}\)(NHC)\(_{2}\)]\(^{+}\) is reported. Starting from the literature known Ni(0) complexes [Ni(Mes\(_{2}\)Im)\(_{2}\)] 1, [Ni(Mes\(_{2}\)Im\(^{H2}\))2] 2, [Ni(Dipp\(_{2}\)Im)\(_{2}\)] 3, [Ni(Dipp\(_{2}\)Im\(^{H2}\))\(_{2}\)] 4 and [Ni(cAAC\(^{Me}\))\(_{2}\)] 5 (Mes\(_{2}\)Im=1,3‐bis(2,4,6‐trimethylphenyl)‐imidazolin‐2‐ylidene, Mes\(_{2}\)Im\(^{H2}\)=1,3‐bis(2,4,6‐trimethylphenyl)‐imidazolidin‐2‐ylidene, Dipp\(_{2}\)Im=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene, Dipp\(_{2}\)Im\(^{H2}\)=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolidin‐2‐ylidene, cAAC\(^{Me}\)=1‐(2,6‐diisopropylphenyl)‐3,3,5,5‐tetramethylpyrrolidin‐2‐yliden), their oxidized Ni(I) analogues [Ni\(^{I}\)(Mes\(_{2}\)Im)\(_{2}\)][BPh\(_{4}\)] 1\(^{+}\), [Ni\(^{I}\)(Mes\(_{2}\)Im\(^{H2}\))\(_{2}\)][BPh\(_{4}\)] 2\(^{+}\), [Ni\(^{I}\)(Dipp\(_{2}\)Im)\(_{2}\)][BPh\(_{4}\)] 3\(^{+}\), [Ni\(^{I}\)(Dipp\(_{2}\)Im\(^{H2}\))\(_{2}\)][BPh\(_{4}\)] 4\(^{+}\) and [Ni\(^{I}\)(cAAC\(^{Me}\))\(_{2}\)][BPh\(_{4}\)] 5\(^{+}\) were synthesized by one‐electron oxidation with ferrocenium tetraphenyl‐borate. The complexes 1\(^{+}\)–5\(^{+}\) were fully characterized including X‐ray structure analysis. The complex cations reveal linear geometries in the solid state and NMR spectra with extremely broad, paramagnetically shifted resonances. DFT calculations predicted an orbitally degenerate ground state leading to large magnetic anisotropy, which was verified by EPR measurements in solution and on solid samples. The magnetic anisotropy of the complexes is highly dependent from the steric protection of the metal atom, which results in a noticeable decrease of the g‐tensor anisotropy for the N‐Mes substituted complexes 1\(^{+}\) and 2\(^{+}\) in solution due to the formation of T‐shaped THF adducts.
KW  - Alkyl(amino)carbene
KW  - EPR spectroscopy
KW  - Metalloradicals
KW  - Nickel ComplexCyclic
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293702
VL  - 2022
IS  - 31
ER  - 
TY  - JOUR
A1  - Krämer, Felix
A1  - Luff, Martin S.
A1  - Radius, Udo
A1  - Weigend, Florian
A1  - Breher, Frank
T1  - NON‐Ligated N‐Heterocyclic Tetrylenes
JF  - European Journal of Inorganic Chemistry
N2  - We report on the synthesis of N‐heterocyclic tetrylenes ligated by the NON‐donor framework 4,5‐bis(2,6‐diisopropylphenyl‐amino)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene. The molecular structures of the germylene (3), stannylene (4) and plumbylene (5) where determined by X‐ray diffraction studies. Furthermore, we present quantum chemical studies on the σ‐donor and π‐acceptor properties of 3–5. Additionally, we report on the reactivity of the tetrylenes towards the transition metal carbonyls [Rh(CO)\(_{2}\)Cl]\(_{2}\), [W(CO)\(_{6}\)] and [Ni(CO)\(_{4}\)]. The isolated complexes (6 and 7) show the differing reactivity of NHTs compared to NHCs. Instead of just forming the anticipated complex [(NON)Sn−Rh(CO)\(_{2}\)Cl], 4 inserts into the Rh−Cl bond to afford [(NON)Sn(Cl)Rh(CO)(C\(_{6}\)H\(_{6}\))] (6, additional CO/C6H6 exchange) and [(NON)Sn(Cl)Rh\(_{2}\)(CO)\(_{4}\)Cl] (7). By avoiding halogenated transition metal precursors in order to prevent insertion reactions, germylene 3 shows “classical” coordination chemistry towards {Ni(CO)3} forming the complex [(NON)Ge−Ni(CO)\(_{3}\)] (8).
KW  - Germylenes
KW  - heterocyclic tetrylenes
KW  - hetrocyclic tetrylene complexes
KW  - Plumbylenes
KW  - Stannylenes
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262586
VL  - 2021
IS  - 35
SP  - 3591
EP  - 3600
ER  -