Conformational investigation of two isomeric chiral porphyrins: A convergent approach with different techniques

The conformation in solution of two atropisomeric meso-tetrabinaphthyl porp hyrins, used as catalytic precursors in asymmetric synthesis, was studied b y means of experimental (H-1-NMR ROESY, UV-Vis, and circular dichroism) and computational (semiempirical structure optimization, DeVoe's coupled oscil lators calculations) methods. UV-Vis and CID spectra are calculated for sev eral molecular models, with a systematic sampling of the conformational spa ce, and compared to the experimental ones, leading to a structural hypothes is which is confirmed by NMR and PM3. Chirality 13:548-555, 2001. (C) 2001 Wiley-Liss, Inc.