A Synthetic Strategy for Cofacial Porphyrin-Based Homo- and Heterobimetallic Complexes

We present a straightforward and generally applicable synthesis route for cofacially linked homo‐ and heterobimetallic porphyrin complexes. The protocol allows the synthesis of unsymmetrical aryl‐based meso‐meso as well as β‐meso‐linked porphyrins. Our method significantly increases the overall yield for the published compound known as o‐phenylene‐bisporphyrin (OBBP) by a factor of 6.8. Besides the synthesis of 16 novel homobimetallic complexes containing Mn$^{III}$, Fe$^{III}$, Ni$^{II}$, Cu$^{II}$, Zn$^{II}$, and Pd$^{II}$, we achieved the first single‐crystal X‐ray structure of an unsymmetrical cofacial benzene‐linked porphyrin dimer containing both planar‐chiral enantiomers of a Ni$^{III}$$_{2}$ complex. Additionally, this new methodology allows access to heterobimetallic complexes such as the Fe$^{III}$‐Ni$^{II}$ containing carbon monoxide dehydrogenase active site analogue. The isolated species were investigated by various techniques, including ion mobility spectrometry, DFT calculations, and UV/Vis spectroscopy. This allowed us to probe the influence of interplane distance on Soret band splitting.