Synthese von Dichlorgallan HGaCl₂

Lewis Base Adducts of Heavier Group 13 Halohydrides – Not Just Aspiring Trihydrides!

“…Although it took until 1989 to confirm the structure of gallane as a dimer,24 two distinct methods for the preparation of halogallanes were reported as early as 1965 by the groups of Greenwood25 and Schmidbaur 26. The former of these resulted from an attempt to isolate uncoordinated gallane ({GaH 3 } n ) by the treatment of solid [GaH 3 (NMe 3 )] with anhydrous hydrogen chloride gas.…”

“…Since their landmark synthesis of dichlorogallane,26 Schmidbaur and co‐workers have prepared several dichlorogallanes supported by pyridine21,30a or phosphane ligands27 (Scheme ) by addition of the free ligands to the dichlorogallane dimer. Many of these products have been the subject of reactivity studies (see Section 3).…”

“…Roesky and co‐workers have used [AlClH 2 (NMe 3 )], prepared by the reaction of trimethylsilylchloride with trimethylaminealane, as a precursor to several carbaalanate complexes (vide infra) 73. This chlorination method mirrors the Schmidbaur preparation of dichlorogallane using a metal trichloride and trimethylsilane 26. The chlorination of an aluminium hydride using silylchlorides was first reported by Power and co‐workers 74…”

Coordination compounds of methyl gallium hydrides

“…In summary, it appears that the compounds Me,NGaH,Me and Me,NGaHMe, are comparable to Me,NGaH, in thermal stability and much more stable thermally than the uncoordinated alkylgallanes (8,27). However, the gallane derivatives are much less stable than the corresponding borane (1 5) and alane (16) compounds.…”

Molecular Dialane and Other Binary Hydrides

“…The first step of this synthesis is a dehalosilylation reaction of GaCl 3 with Me 3 SiH, first discovered by Schmidbaur et al, which yields Cl 2 GaH. [10] The addition of two equivalents of Me 3 SiH yields the very sensitive ClGaH 2 , [11] which then can be treated with lithium tetrahydrogallate to yield gallane in a solvent-free reaction that employs an all-glass apparatus at pressures below 10 À4 Torr; gallane is stable only up to 240 K. [12] Structural determination by gasphase electron diffraction ( Figure 1) required the construction of a special gas-inlet nozzle and was even then only possible with difficulty due to the reaction of gallane with the photographic emulsion at pressures of about 10 À6 mbar. A determination of the solid-state structure of GaH 3 has not yet been possible because of thermal instability and the resulting difficulties with crystal growth from the liquid phase.…”