The Synthesis of Cofacial Porphyrin Dimers
Hiom, J., Paine III, J.B., Zapf, U., and David Dolphin
Can. J. Chem
Cofacial dimeric porphyrins I (m = n = 8, 6, R = R1 = Et; m = n = 3, R = R1 = octyl; m = 6, n = 4, R = R1 = Et; m = 4, n = 3, R = octyl, R1 = Et) joined by two hydrocarbon chains has been prepared using a bis-porphyrin already linked by a single hydrocarbon chain. When each porphyrin bears an acetylenic group, Cu-catalyzed coupling followed by catalytic hydrogenation gives the doubly linked cofacial porphyrin. However, a far superior and more flexible route, involving the use of a dimeric biladiene-ac, gives the same cofacial porphyrin in one step. This latter route has been used to prepare I.