The association constants [Kassoc, M−1] measured in DMSO-d6 and CIS values (in italics) [ppm] for anion of 2 associated with substituted ureas and the linear correlation coefficient for Kassoc = f (substituent constant) (a–c, trans).
| Guest | H4 | H6 | H7 | H8 | H12 |
|---|---|---|---|---|---|
| a (NMe2) | 200, 0.112 | 200, 0.108 | 150, 0.153 | 130, 0.270 | 170, 0.097 |
| b (OMe) | 240, 0.124 | 300, 0.120 | 220, 0.156 | 170, 0.289 | 280, 0.112 |
| c (H) | 430, 0.139 | 480, 0.133 | 300, 0.200 | 190, 0.359 | 400, 0.126 |
| c (H, cis) | 300, 0.187 | 260, 0.135 | 300, 0.369 | 250, 0.156 | 250, 0.169 |
| R a | 0.97, 0.96 | 0.93, 0.97 | 0.97, 0.78 | 1.00, 0.87 | 0.97, 0.98 |
a
Correlation coefficient for the trans form.