Figure 6.

¹H NMR spectra of 1:1 complexes of strapped dibromoporphyrins 7a–c with pyridine in CD₂Cl₂ at 193 K (500 MHz). Signals belonging to the out and in complexes are displayed in blue and red, respectively, with overlapping signals displayed in purple. In the in complex, the reduced symmetry of the molecule leads to splitting of the β pyrrole proton signals into 4 doublets (β_1-st and β_2-st refer to the β protons on the strap side), and restricted conformational freedom leads to splitting of the strap proton signals (noted for example a₁ and a₂ for the a protons).