Ein planar vierfach koordiniertes Boratom als Ligand für vier Metalle

Abstract

Bor im Quadrat: Vierfach koordinierte Bor‐, Kohlenstoff‐ und Stickstoffatome sind in ihren Verbindungen üblicherweise tetraedrisch umgeben. Ausgehend von dreikernigen, koordinativ ungesättigten Boridokomplexen konnten nun die ersten vierkernigen Boridokomplexe mit nahezu planar umgebenen, vierfach koordinierten Boratomen erhalten werden (siehe Schema). Die Bindungswinkelsummen um die Boratome in diesen beiden Komplexen betragen 362.4° und 364.6°.

A Simple Link between Hydrocarbon and Borohydride Chemistries

“…Methane: Methane has a unique equivalent borohydride, that is, BH 4 À . [7] Ethane: From C 2 H 6 and by electronic transmutation we can generate the CBH 6 À and B 2 H 6 2À analogues of ethane shown in Figure 1. As said before, B 2 H 6 2À was already considered to be an ethane analogue by Olson and Boldyrev.…”

“…Similarly, BH 4 À is the boron-containing hydride equivalent of CH 4 . [7] The process of transforming the hydrocarbons to borohydrides through substitution of all or a certain number of C atoms by B and addition of as many extra electrons as substituted C atoms in the original hydrocarbon has been called electronic transmutation. [6] This idea was already used some years ago by the same group to predict Li 6 B 6 H 6 with the B 6 H 6 6À kernel, as a planar all-boron aromatic molecule equivalent to benzene.…”

“…Thus, for instance, the Li 2 B 2 H 6 compound contains the B 2 H 6 2− unit, which is an isoelectronic and isostructural analogue of ethane. Similarly, BH 4 − is the boron‐containing hydride equivalent of CH 4 7. The process of transforming the hydrocarbons to borohydrides through substitution of all or a certain number of C atoms by B and addition of as many extra electrons as substituted C atoms in the original hydrocarbon has been called electronic transmutation 6.…”