Table 1. DFT calculations of relative deprotonation, binding, and complexation energies of selected Cu(ii):HCT-13 complexes and Cu(ii) to Cu(i) reduction energies.

Compound	Rel. deprotonation energy (kcal mol–1)	Rel. binding energy (kcal mol–1)	Rel. complexation energy (kcal mol–1)	Rel. energy of reduction (kcal mol–1)
HCT-5	0	0	0	–0.9
HCT-11	–4.6	0.6	–4	0
HCT-12	–9.6	4.3	–5.5	–1.5
HCT-13	–10.5	4.4	–6.1	–1.5