{Ge₈[Fe(CO)₄]₈}⁷⁻: an anionic cubic germanium-iron-cluster featuring an unpaired electron

Abstract

Within the reaction of a metastable Ge(I)Cl solution and Na2Fe2(CO)8 the anionic cubic cluster compound {(thf)14Na6Ge8[Fe(CO)4]8}− (3) is obtained. The open shell character of 3 is proven by EPR spectroscopy....

Facile Synthesis of an Octagermacubane with Two Three‐Coordinate Germanium(0) Atoms and its Unique Radical Anion

“…Both 24 and 25 have very low solubility in common organic solvents preventing acquisition of their liquid-state NMR spectra, similarly to 18. The solid-state 29 Si NMR spectrum of 24 displays a single resonance at 28.8 ppm, upfield shifted compared to the solid-state 29 Si NMR chemical shift of 18 (δ = 34.6 ppm). The solid-state 29 Si NMR spectrum of 25 shows two peaks at 22.3 ppm and 25.5 ppm, consistent with the presence of two non-equivalent sets of silyl substituents.…”

“…The solid-state 29 Si NMR spectrum of 24 displays a single resonance at 28.8 ppm, upfield shifted compared to the solid-state 29 Si NMR chemical shift of 18 (δ = 34.6 ppm). The solid-state 29 Si NMR spectrum of 25 shows two peaks at 22.3 ppm and 25.5 ppm, consistent with the presence of two non-equivalent sets of silyl substituents. 24 and 25 are interesting precursors for further chemical manipulations, such as coupling reactions possibly producing oligo-octagermacubanes.…”

“…EPR spectra of the reaction mixtures at 330 K, show a strong signal with a g-value of 2.028 assigned to radical anions 26 (Figure 2). The splitting pattern of the EPR signal shows characteristic splitting to 10 signals from two 73 Ge nuclei (I = 9/2) with hfcc value a( 73 Ge) = 7.5 G, and coupling with six 29 Si nuclei with hfcc a( 29 Si) = 11.8 G (for 26-Li, Figure 2). The EPR spectrum of 26-Na is very similar (see Supporting Information).…”

“…Therefore, we carried out joint thermolysis (hexane, 100 °C, 24 hrs., sealed tube) of a 1 : 1 mixture of tris(silyl)germane 9 and bis(silyl)germane 17, producing a dark brown solution. Both 9 and 17 were nearly completely consumed, according to 29 Si NMR spectroscopy. Upon cooling to room temperature, green crystals of octagermacubane 18 were obtained in a surprisingly good yield of ca.…”

“…[21] Unfortunately, 18 has a very low solubility in common organic solvents (e.g., hexane, benzene, and THF), preventing the acquisition of its liquid-state NMR spectrum. However, we measured the solid-state 29 Si NMR spectrum of 18, which showed a single resonance at 34.6 ppm for the silyl substituent, similar to that of octastannacubane (tBu 2 MeSi) 8 Sn 8 (6) (δ = 38.1 ppm). [3i, 22] Natural Bond Orbital (NBO) [23] analysis of 18 shows a lone pair orbital on the Ge 0 atoms having mainly s-character with a very small p-orbital contribution (sp 0.12 ).…”