A Redox‐Switchable Germylene and its Ligating Properties in Selected Transition Metal Complexes

Abstract

The synthesis, structure, and full characterization of a redox-switchable germylene based on a [3]ferrocenophane ligand arrangement, [Fc(NMes) Ge] (4), is presented. The mesityl (Mes)-substituted title compound is readily available from Fc(NHMes) (2) and Ge{N(SiMe ) } , or from the dilithiated, highly air- and moisture-sensitive compound Fc(NLiMes) ⋅3 Et O (3) and GeCl . Cyclic voltammetry studies are provided for 4, confirming the above-mentioned view of a redox-switchable germylene metalloligand. Although several 1:1 Rh and Ir complexes of 4 (5-7) are cleanly formed in solution, all attempts to isolate them in pure form failed due to stability problems. However, crystalline solids of [Mo(κ Ge-4) (CO) ] (8) and [W(κ Ge-4) (CO) ] (9) were isolated and fully characterized by common spectroscopic techniques (8 by X-ray diffraction). DFT calculations were performed on a series of model compounds to elucidate a conceivable interplay between the metal atoms in neutral and cationic bimetallic complexes of the type [Rh(κ E-qE)(CO) Cl] (qE=[Fc(NPh) E] with E=C, Si, Ge). The bonding characteristics of the coordinated Fc-based metalloligands (qE/qE ) are strongly affected upon in silico oxidation of the calculated complexes. The calculated Tolman electronic parameter (TEP) significantly increases by approximately 20 cm (E=C) to 25 cm (E=Si, Ge) upon oxidation. The change in the ligand-donating abilities upon oxidation can mainly be attributed to Coulombic effects, whereas an orbital-based interaction appears to have only a minor influence.

Stable N‐Heterocyclic Germylenes of the Type [Fe{(η5‐C5H4)NR}2Ge] and Their Oxidation Reactions with Sulfur, Selenium, and Diphenyl Diselenide

“…These compounds of the type [{Fe(η 5 ‐C 5 H 4 ‐N R ) 2 }Ge] ( 1R Ge, R = SiMe 3 , CH 2 t Bu, t Bu, Mes) constitute the first N‐heterocyclic tetrylenes bearing redox‐active substituents . The mesityl homologue 1Mes Ge was studied independently also by Breher and co‐workers . In this context we note that the only ferrocene‐derived germylene with dicoordinate Ge II known to date is Fc* 2 Ge [Fc* = 2,5‐bis(3,5‐di‐ tert ‐butylphenyl)‐1‐ferrocenyl], which was published very recently by Sasamori .…”

Reactivity of a Base-Stabilized Germanium(I) Dimer toward Group 9 Metal(I) Chloride and Dimanganese Decacarbonyl

“…Yield: 0. 17 [(LGe)μ-{Mn(CO) 4 }] 2 (7). A solution of 1 (0.39 g, 0.49 mmol) in toluene (12 mL) was added dropwise to a stirred suspension of Mn 2 (CO) 10 (0.20 g, 0.51 mmol) in toluene (12 mL) at room temperature.…”

Reactive Dimerization of an N‐Heterocyclic Plumbylene: C−H Activation with PbII

“…[5] We herein report N-heterocyclic plumbylenes of the type [Fe{(h 5 -C 5 H 4 )NR} 2 PbD]( 1Pb), the heavy analogues of our stable NHCs with a1 ,1'-ferrocenediyl (fc) backbone,w hose ambiphilicity allowed for smallmolecule activation reactions unprecedented for diaminocarbenes. [7] This study revealed that SiMe 3 substituents at the Na toms are suitable to establish reversible redox-chemical behaviour of such NHTs,w hich is why we aimed at the synthesis of [Fe{(h 5 -C 5 H 4 )NSiMe 3 } 2 PbD]( 1aPb). [7] This study revealed that SiMe 3 substituents at the Na toms are suitable to establish reversible redox-chemical behaviour of such NHTs,w hich is why we aimed at the synthesis of [Fe{(h 5 -C 5 H 4 )NSiMe 3 } 2 PbD]( 1aPb).…”