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 MnIII , FeIII , NiII , CuII , ZnII , and PdII , we achieved the first single-crystal X-ray structure of an unsymmetrical cofacial benzene-linked porphyrin dimer containing both planar-chiral enantiomers of a NiII 2 complex. Additionally, this new methodology allows access to heterobimetallic complexes such as the FeIII -NiII 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.