Table 4. Experimental Difference in Enthalpy ΔΔH_exp^‡, Theoretical Activation Enthalpy for Photosubstitution ΔH_1, comp, and Activation Enthalpy for Nonradiative Decay ΔH_2, exp^‡a.

solvent	complex	ΔΔHexp‡ (kJ/mol)	ΔH1, comp‡ (kJ/mol)	ΔH2, exp‡ (kJ/mol)
waterb	[1a](PF6)2	22.9 ± 0.03	37.5	14.6
	[2a](PF6)2	57.1 ± 0.03	64.7	7.6
acetonitrile	[1a](PF6)2	23.9 ± 0.02	52.2	28.3
	[2a](PF6)2	–20.6 ± 0.19	38.3	58.9

^aCalculated according to eq 12

^bWater:acetone 1:1 for experimental values.