E-mail: stephan. E-mail: robert. Quantum chemical calculations were employed to support the experimental findings. Furthermore, the formation of a Ga—Ga bond upon the oxidative addition should equip 1 with increased reducing power compared to the mononuclear species. Single crystals of 1-Al were obtained from a saturated benzene solution by storage at room temperature Scheme 1 , bottom.
Its molecular solid-state structure confirms the formation of a rare Ga I —Al III Lewis acid—base adduct, of which only three examples have yet been structurally characterised. The Ga1—Ga2 2. The sum of the C—Al—C bond angles in 1-Al Addition of 1 to solutions of 2 -E C 6 F 5 3 immediately afforded bright yellow solutions of 1-B and 1-Al , respectively, and compound 2 Scheme 2a. The cross-over experiments proved the enhanced Lewis basicity of 1 compared to 2 , which is likely induced by the Ga I —Ga I donor—acceptor interaction.
However, the significance of the experiment might be biased due to additional Al—F interaction in 3-B. In contrast, the reaction of 1 with 3-B is endergonic by In order to identify the expected reaction products, i.
Compounds 1-Cl 2 and 1-I 2 are stable in the solid-state and in solution under air- and moisture-free conditions. The halide substituents in the dihalodigallanes adopt syn -periplanar conformations with respect to the Ga—Ga bond torsion angles X—Ga—Ga—X: 1-Cl 2 This likely results from the higher reaction temperatures required to overcome the activation barrier for the halogen transfer imposed by the sterically demanding environments of the Ga centres in 1 and 2.
However, the cross-over experiments undoubtedly proved the higher reducing power of binuclear 1 compared to mononuclear 2. The reactions are consistent with one-electron oxidation per Ga centre each in 1 and a two-electron reduction of the Ga centre in 2-X 2 , while the syn -periplanar arrangement of the halide substituents in 1-Cl 2 and 1-I 2 supports a suprafacial addition of the halogen atoms to 1.
