NMR spectroscopy and crystal structure of [Me2GaP(H)SitBu3]2 and theoretical investigations of the model compounds [R′2GaP(H)R″]2

The dimeric phosphanylgallanes [R′2GaP(H)SitBu3]2 with R′ = Me, Cl [Inorg. Chem. 43 (2004) 3756] were synthesized by metathesis reactions. The obtained compounds were characterized by NMR spectroscopy and single crystal X-ray crystallography. In order to compare the structures and to compare the relative energies of isomers, theoretical investigations were performed on the phosphanylgallane model compounds of the type [R′2GaP(H)R″]2 by using the hybrid density functional theory (B3LYP). Different 1,3- and 2,4-substituted dimeric phosphanylgallanes with R′ = Cl, Me, Et and R″ = H, SiH3 and SiMe3 as well as their monomers were calculated and could be correlated to the cis–trans isomerization equilibrium constants which were accessible by integration of suitable 31P NMR signals.

The dimeric phosphanylgallanes [R′2GaP(H)SitBu3]2 with R′ = Me, Cl show unusual large 2J  (P,P) coupling constants. Therefore, the molecular structures and energies of the phosphanylgallane model compounds of the type [R′2GaP(H)R″]2 were determined by using the hybrid density functional theory (B3LYP).Figure optionsDownload as PowerPoint slide