Germa‐closo‐dodecaborate: An Ambident and Flexible Coordinating Ligand

Abstract

By following a simple one‐pot procedure that starts with FeBr2 and triphos [MeC(CH2PPh2)3] or the dimer [Ru2(μ‐Cl)3(triphos)2]Cl in reaction with the nucleophile [Bu3MeN]2[GeB11H11] in acetonitrile, the zwitterionic acetonitrile adducts [M(GeB11H11)(triphos)(MeCN)2] [M = Fe (1), M = Ru (2)] were isolated in good yield. By means of a facile η1(Ge) to η3(B–H) rearrangement, 1 and 2 can be converted into [M(GeB11H11)(triphos)] [M = Fe (3), M = Ru (4)]. The nucleophilicity of the germanium cluster vertex in the iron derivative 3 is high enough to react with [Mo(CO)5(thf)] to give the bimetallic complex [(triphos)Fe(GeB11H11)(MoCO)5] (5), which contains an ambident coordinating germaborate moiety. The new compounds have been characterized by single‐crystal X‐ray diffraction and elemental analysis. Soluble complexes were also investigated by 1H, 11B, and 31P NMR spectroscopy in solution. In the case of the insoluble complex 1, solid‐state 31P NMR spectroscopy was carried out.

1,2‐Carbagerma‐closo‐dodecaborate as a Germanium Ligand in Coordination Chemistry – Synthesis, Structure and Reactivity

“…The Ru-Ge bond of 2.3978(4) Å is similar to the Ru-Ge bond lengths reported for [C 6 H 6 Ru(CO)(GeCl 3 ) 2 ] at 2.403(2) Å. [21] Longer Ru-Ge bonds are quoted at 2.4455(4) Å for [Ru(Cl)(CO)-trans-(PPh 3 ) 2 (GeMe 3 )] [22] and 2.5239(6) Å for [Ru(GeB 11 H 11 )(MeCN) 2 (triphos)] [9] due to considerably different metal coordination states combined with the steric and electronic effects of the various ligands.…”

“…We have also explored the coordination chemistry of the homologous germanium di-anion, germa-closo-dodecaborate [GeB 11 H 11 ] 2-(A). [4,[7][8][9] We have also synthesised the new dianions [Sn 2 2-are replaced by tin or germanium atoms. [10] We expanded this area of heteroborates by synthesizing the new cluster monoanion [SnCB 10 H 11 ] -(F in Scheme 1) where one [BH] -unit is formally replaced by an isolobal CH unit in [SnB 11 H 11 ] 2-.…”

Synthesis and Coordination Chemistry of a Chelating P–Sn Ligand Based on Stanna‐closo‐dodecaborate

“…It turned out that the dianionic closo-borates [GeB 11 H 11 ] 2-, [SnB 11 H 11 ] 2-, and [Sn 2 B 10 H 10 ] 2are versatile ligands in coordination chemistry, offering strong trans influence and labile coordination properties. [5] Furthermore, the electron-donor ability of the dianionic ligands was verified in coinage-metal coordination chemistry: clusters based on bond formation between coinage metals, due to dispersive interactions, are the main structural motif in this chemistry. [6] A couple of years ago, we studied the coordination chemistry of the germa-and stanna-closo-dodecaborate nucleophiles at a palladium xantphos electrophile.…”

Boron, aluminium, gallium, indium and thallium

“…Wesemann and co-workers have described the synthesis and coordination chemistry of the germa-closo-dodecaborate dianion, [GeB 11 H 11 ] 2À , 96 and the carbogerma-closododecaborate anion, [GeCB 10 H 11 ] À , 97 towards transition metal moieties. In related studies the coordination chemistry of the distanna-closo-dodecaborate, [Sn 2 B 10 H 10 ] 2À , 98 and the diphosphaborane, P 2 B 10 H 10 have also been reported.…”