Abstract
The coordination of GeH
4
to the ruthenium complex RuH
2
(η
2
-H
2
)
2
(PH
3
)
2
can lead to oxidative addition or σ-bond coordination of the germane. The corresponding germyl or σ-isomers have been optimized by DFT using the B3LYP hybrid functional. The most stable isomer corresponds to a germyl bis(dihydrogen) complex RuH(GeH
3
)(η
2
-H
2
)
2
(PH
3
)
2
(
1T-b1
) with
trans
phosphines. It is only 2 kcal mol
−1
below the σ-isomer RuH
2
(η
2
-H
2
)(η
2
-H-GeH
3
)(PH
3
)
2
(
1C-a1
). This is in contrast to what has been previously observed in the corresponding silane chemistry, in which σ-coordination was favoured. However, calculated binding energies for GeH
4
or SiH
4
to the RuH
2
(H
2
)(PH
3
)
2
fragment are very similar (−21.3 and −22.2 kcal mol
−1
, respectively). The nature of the metal-germane interaction is analysed by natural bond orbital (NBO) calculations.
A series of σ-germane and germyl complexes has been optimized at the DFT B3LYP level. The σ-isomer
C-a
is above the germyl isomer by only 2 kcal mol
−1
.