Table 2.

Calculated free energies for loss of an axial Met ligand [constrained at different Cu–S(Met) distances] from a reduced copper site at room temperature

Model, Å*	ΔE†	ΔH‡	ΔS	TΔS	ΔG
2.5§	5.8 (0.5)	4.7 (0)	37 (38)	10.9 (11.3)	−6.2 (11.9)
2.9¶	5.0 (0.4)	3.8	34	10.1	−6.3
4.0¶	4.6 (0)	3.2	21	6.4	−3.2

*Reduced Cu site model: [Cu(Im)₂(SCH₃)(S(CH₃)₂)].

^†Total electronic energy change for loss of Met ligand.

^‡ΔE with zero-point and thermal corrections included: H = E_electronic + E_ZPE + E_vib + E_rot + E_trans + RT. ZPE = zero point energy. The results of PCM calculations are shown in the parentheses. ΔE, ΔH, TΔS, and ΔG are in kcal/mol, and ΔS is in cal/mol·K.

^§The d_{Cu–S(thioether)} distance is obtained from full geometry optimization.

^¶The d_{Cu–S(thioether)} distance is constrained as indicated.