Stable Platinum(IV) Corroles: Synthesis, Molecular Structure, and Room-Temperature Near-IR Phosphorescence

[Image: see text] A series of stable Pt(IV) corrole complexes with the general formula Pt(IV)[TpXPC](m/p-C(6)H(4)CN)(py), where TpXPC(3–) is the trianion of a tris(p-X-phenyl)corrole and X = CF(3), H, and CH(3), has been synthesized, affording key physicochemical data on a rare and elusive class of metallocorroles. Single-crystal X-ray structures of two of the complexes revealed very short equatorial Pt–N distances of 1.94–1.97 Å, an axial Pt–C distance of ∼2.03 Å, and an axial Pt–N distance of ∼2.22 Å. The complexes exhibit Soret maxima at ∼430 nm, which are essentially independent of the meso-aryl para substituents, and strong Q bands with the most intense peak at 595–599 nm. The substituent-independent Soret maxima are consistent with an innocent Pt(IV)–corrole(3–) description for the complexes. The low reduction potentials (−1.45 ± 0.08 V vs saturated calomel reference electrode) also support a highly stable Pt(IV) ground state as opposed to a noninnocent corrole(•2–) description. The reductions, however, are irreversible, which suggests that they involve concomitant cleavage of the Pt–aryl bond. Unlike Pt(IV) porphyrins, two of the complexes, Pt(IV)[TpXPC](m-C(6)H(4)CN)(py) (X = CF(3) and CH(3)), were found to exhibit room-temperature near-IR phosphorescence with emission maxima at 813 and 826 nm, respectively. The quantum yield of ∼0.3% is comparable to those observed for six-coordinate Ir(III) corroles.