H Bond Coordination and Activation

Alkane coordination and C-H bond cleavage have been extensively studied theoretically which is important because of the instability of alkane complexes— they are either are too weak to be observed or rapidly proceed to products of OA. In the latter case, computed binding energies of the transient r complexes seem sufficient to allow observation, but an arrested complex analogous to an elongated 

H-H or Si-H a complex has not been isolated (stretched agostic C-H interactions are known). As will be shown in Section 12.4, clear evidence exists for intermediate alkane a complexes in OA/RE of C-H bonds. Equilibria between M(i/2-RH) and 

M(R)(H) tautomers has not been seen perhaps because the weak M C-H back-bonding prevents a good balance of a donation and backdonation (BD). 

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