Application of MCD Spectroscopy and TD‐DFT to Nonplanar Core‐Modified Tetrabenzoporphyrins: Effect of Reduced Symmetry on Nonplanar Porphyrinoids

摘要: The optical spectra of a series core-modified tetrabenzoporphyrins were analyzed to determine the effects core modification, ligand folding, and partial benzo substitution at periphery on electronic structure by using magnetic circular dichroism (MCD) NMR spectroscopy, X-ray crystallography, cyclic differential pulse voltammetry, TD-DFT calculations. Planar 21-carba-, 21-thia-, 21,23-dithia-, 21-oxa-23-thiatetrabenzo[b,g,l,q]porphyrins reported previously studied together with unreported 21-oxa- 21-carba-23-thiatetrabenzo[b,g,l,q]porphyrins. properties these compounds are compared those tetrabenzo[b,g,l,q]-, 5,10,15,20-tetraphenyl-, 5,10,15,20-tetraphenyltetrabenzo[b,g,l,q]-21-thia-, 5,10,15,20-tetraphenyltetrabenzodithia-, 5,10,15,20-tetraphenyldibenzo[g,q]-21,23-dithia-, 5,10,15,20-tetraphenyldibenzo[b,l]-21,23-dithia-, 5,10,15,20-tetraphenyltribenzo[g,q,l]-21-thia-, 5,10,15,20-tetraphenylbenzo[b]-21-thiaporphyrins. Michl's perimeter model Gouterman's four-orbital used conceptualize results account for red shifts commonly observed in spectral bands nonplanar porphyrinoids.