Reaction profile (in kcal mol⁻¹) for the oxidative insertion of iron and palladium model catalysts into H₃C–X bonds (X = H, Cl, CH₃)^a.

		RC	TS	P
1Fe(CO)4	C–H	−1.3	10.4	0.8
	C–Cl	−9.0	25.5	−15.1
	C–C	0.1	48.0	10.2
3Fe(CO)4	C–H	0.0	64.4	45.2
	C–Cl	0.0	43.3	29.4
	C–C	−0.1	76.9	51.1
1Fe(CO)42−	C–H	−2.4	74.1	66.3
Pd(PH3)2	C–H	−0.2	30.5	28.1
	C–Cl	−0.5	30.6	−8.0
	C–C	−0.3	51.7	29.8
Pd(CO)2	C–H	−0.0	33.4	31.7
	C–Cl	−0.2	34.7	5.1
	C–C	−0.1	53.9	32.8

^aComputed at ZORA-OPBE/TZ2P. ¹Fe(CO)₄ is 0.2 kcal mol⁻¹ less stable than ³Fe(CO)₄.