Silver(III)⋅⋅⋅Silver(III) Interactions that Stabilize the syn Form in a Porphyrin Dimer Upon Oxidation

The interaction between two Ag^II porphyrins, connected covalently through a highly flexible ethane bridge, in a metalloporphyrin dimer has been investigated upon stepwise oxidation. X‐ray structure determination of one and two‐electron oxidized complexes has clearly revealed only metal‐centered oxidation that results in short Ag−N (porphyrin) distance with large distortion in the porphyrin macrocycle. The 2e‐oxidized complex exhibits significant metallophilic interaction in the form of a close Ag^III⋅⋅⋅Ag^III contact that brings two porphyrin rings more cofacial with syn ‐conformation, which would otherwise stabilize in an anti ‐form. The interaction also leads to an intense emission peak at 546 nm at 77 K in the photoluminescence study.