Photochemical Cleavage of Pentamethylcyclopentadienyl−Gallium Bonds: An Alternative Approach to the Formation of Digallanes

The novel digallanes (3) (Dipp = 2,6-diisopropylphenyl) and (4) (Dep = 2,6-diethylphenyl)
were obtained in quantitative yield by photolysis of the
1-galla-2,5-diazoles
(1) and (2), respectively. This alternative approach to the synthesis of
digallanes demonstrates the efficiency of the Cp* moiety
as the leaving group in the formation of metal−metal
bonds. Compounds 3 and 4 were characterized by
spectroscopic and analytical data. Compound 3 could
further be characterized by X-ray crystallography; its
molecular structure is compared with the structures of
some other digallanes. Density functional calculations
for differently substituted digallanes are presented.