NCN-Type Pincer Complexes of Subporphyrinatoboron(III)

The first NCN-type subporphyrin pincer complexes 3Pd and 3Pt have been synthesized via Suzuki coupling of 2,13-diborylsubporphyrin with 2-iodopyridine, followed by metalation with PdCl₂(MeCN)₂ or K₂PtCl₄, respectively. 2,13-Diiminosubporphyrin 4 was also prepared via formylation of 2,13-dilithiosubporphyrin followed by imination with aniline but was found to be unsuitable as a precursor of organometallic species. The complexes 3Pd and 3Pt displayed perturbed optical properties presumably due to the d­(metal)π­(subporphyrin) orbital interactions.