Table 1. Dissociation constants and extents of helicity for peptide–metal complexes. Discussion of binding models, formulas for calculating helicity, and additional figures can be found in the ESI. The helicity of the metal-free peptide was measured in 60% TFE to obtain the maximum expected helical signal.
| Metal | K d, His–Phen HCM (M) | K d, free Phen1 (M) | Calculated helicity (at 25 °C) | Percent of maximum helicity |
| Metal-free | N/A | N/A | 17% | 30% |
| CoII | 3(2) × 10–8 | 8.0 × 10–8 | 38% | 69% |
| NiII | 3(2) × 10–11 | 3.9 × 10–8 | 43% | 77% |
| CuII | 6(5) × 10–13 | 2.5 × 10–9 | 18% | 32% |
| ZnII | 1.7(7) × 10–8 | 3.7 × 10–7 | 34% | 62% |