1,4‐Di(isopropyl)‐1,4‐diazabutadien als Abfangreagenz für monomere Bruchstücke des Tetragalliumclusters Ga₄[C(SiMe₃)₃]₄ – Bildung eines ungesättigten GaN₂C₂‐Heterocyclus und eines Oxidationsprodukts mit Ga‐O‐O‐Ga‐Gruppe

Abstract

The tetrahedral tetragallium cluster Ga 4 [C(SiMe 3 ) 3 ] 4 (1) dissociates upon dissolution to yield the monomeric fragments Ga-R [R ϭ C(SiMe 3 ) 3 ]. These monomers could be trapped now by the treatment of their solutions with 1,4-di(isopropyl)-1,4-diazabutadiene. The product of the cycloaddition reaction (2) possesses a five-membered GaN 2 C 2 heterocycle with a coordinatively unsaturated gallium atom and an endocyclic CϭC double bond. 2 is rather sensitive towards oxidation by traces of air. The contact with

Reducing GaH and GaC Bonds in Close Proximity to Oxidizing Peroxo Groups: Conflicting Properties in Single Molecules

“…[3] This observation caused us to start more systematic investigations into the formation and isolation of those compounds, which are of particular interest for essentially two reasons: 1) they may be effective oxidants for the transformation of organic or organometallic compounds; 2) the peroxo group may show a singular coordination behavior towards the central aluminium or gallium atoms similar to that one of the isoelectronic hydrazines or hydroxylamines. [4] Bis-or tris(trimethylsilyl)methylaluminium or -gallium compounds proved to be rather insensitive towards an attack of oxygen in former investigations.…”

“…Instead the negative charge at the a-carbon atoms attached to the electropositive aluminium or gallium atoms may be reduced by hyperconjugation, and the reductive power of the E À C bond may be diminished. Two peroxides bearing bis(trimethylsilyl)methyl substituents have been synthesized only recently: A cyclic trigallium triperoxide, [(RGa) 3 (O 2 ) 3 …”

Strongly Oxidizing and Reducing Functions Combined in a Single Compound: An Alkyl Gallium Peroxide Possessing a Nine‐Membered (GaR)3(O2)3 Heterocycle

“…A shorter distance (147.7 pm) occurred in the digallium peroxide mentioned above, which had only terminal gallium atoms. [2] While the Ga-O-O-Ga moiety of that compound is almost planar, with a torsion angle of 1648, a rather acute torsion angle across the OÀO bond (59.08 on average) indicates an approach to the gauche form in 2. Depending on the aggregation state, hydrogen peroxide shows torsion angles between 90 and 1128.…”

“…[1] A digallium peroxide with two alkyl gallium groups terminally attached to a bridging peroxo ligand was isolated in trace quantities. [2] It resulted from the accidental exposure of an organogallium compound to air. Usually, the treatment of such alkyl element compounds with oxygen or suitable peroxo derivatives gives the complete oxidation of all EÀC bonds in the molecules.…”

Persistent Alkylgallium Peroxides – Synthesis of the Cage Compound Na4[(Ga‐R)3(O2)3(O)]2(Et2O)(DABCO) [R = CH(SiMe3)2]

“…A digallium peroxide possessing terminal Ga-C bonds was isolated only in trace quantities. [4] Furthermore, peroxo groups were found in two aluminum compounds which do not contain intact Al-C bonds. [5] Recently the crystal structures of two relatively inert alkylaluminum and -gallium peroxides were reported, which were stabilized by bis(trimethylsilyl)methyl groups.…”