The mechanism of a C-H bond activation reaction in room-temperature alkane solution

Chemical reactions that break alkane carbon-hydrogen (C-H) bonds are normally carried out under conditions of high temperature and pressure because these bonds are extremely strong (~100 kilocalories per mole), but certain metal complexes can activate C-H bonds in alkane solution under the mild conditions of room temperature anti pressure. Time-resolved infrared experiments probing the initial femtosecond dynamics through the nano- and microsecond kinetics to the final stable products have been used to generate a detailed picture of the C-H activation reaction. Structures of all of the intermediates involved in the reaction of Tp*Rh(CO)₂ (Tp* = HB-Pz₃*, Pz* = 3,5-dimethylpyrazolyl) in alkane solution have been identified and assigned, and energy barriers for each reaction step from solvation to formation of the final alkyl hydride product have been estimated from transient lifetimes.