Table 1. Binding Constants (log K) and Binding Energies (E) of the Anions Complexes of L.
| anion | log Ka | log Kb | E (kcal/mol) |
|---|---|---|---|
| F– | >4.0c | 5.1 | 182 |
| Cl– | 3.1 | 3.2 | 107 |
| Br– | 1.9 | 1.7 | 116 |
| I– | <1d | <1e | f |
| SO42– | >4.0 | 6.4 | 217 |
| HSO4– | 2.9 | 2.8 | 97 |
| H2PO4– | 3.0 | 3.1 | 112 |
| NO3– | <1d | <1e | 107 |
| ClO4– | <1d | <1e | 87 |
a
Determined by 1H NMR titrations in DMSO-d6.
b
Determined by UV titrations in DMSO.
c
Slow proton exchange.
d
No appreciable change was observed in 1H NMR spectra.
e
No appreciable change was observed in UV spectra.
f
The 6-31+G(d,p) basis set is not available for iodide.