Incorporating tungsten into the N3 core of a N‐fused porphyrin (NFP; 1) affords high‐valent tungsten(VI)‐NFP complexes, WClO2‐1 and 21‐chlorinated WClO2‐3. The X‐ray structure of WClO2‐1 reveals a distorted octahedral geometry with sitting atop metal coordination. The absorption spectrum of WClO2‐1 displays bathochromically shifted Q‐like bands beyond 1000 nm, indicating an inherently narrow HOMO‐LUMO energy gap. DFT calculations show that the degeneracy of the LUMO and LUMO+1 pair of 1 is significantly resolved by the tungsten(VI) coordination. Conclusively, magnetic circular dichroism (MCD) spectroscopy and cyclic voltammetry provide a rationale for the narrow HOMO‐LUMO energy gap in the “16‐electron” d0 tungsten(VI)‐NFP complexes.

N‐fused porphyrin (NFP) is a unique class of photostable near‐infrared dyes with an 18π aromatic tetrapyrrole macrocyclic skeleton containing a tri‐fused pentacyclic moiety. Here, the synthesis of an iridium complex of N‐fused bilatrienone is reported as the degradation product of Ir‐cyclooctadiene (cod)‐induced oxidative cleavage of NFP under aerobic conditions. Similar to the native bilin chromophores, the ring‐opened complex featured a broken π‐conjugation circuit and exhibited a broad visible absorption band. In contrast, metalation of NFP using an iridium(I)(cod) complex under an inert atmosphere resulted in the formation of a cod‐isomerized (κ1,η3‐C8H12)‐Ir complex.

No abstract