Porphyrins XXII: Fast fluorescence, delayed fluorescence, and quasiline structure in palladium and platinum complexes

• Published in: Journal of molecular spectroscopy 1971, Vol.39 (3), p.410-420
• Main Authors: Callis, J.B, Gouterman, M, Jones, Y.M, Henderson, B.H
• Format: Article
• Language: English
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1016/0022-2852(71)90212-8

Three Pd porphyrins are shown to exhibit fast and delayed fluorescence, while Pt etioporphyrin exhibits only delayed fluorescence. The yield of delayed fluorescence obtained experimentally agrees with the yield calculated from the principle of detailed balance. Fast fluorescence yields from the Pd porphyrins of Φ ff ∼ 3 × 10 −4 imply an uncertainty line broadening of Δ ν ∼ ∼ 0.25 cm −1 . Lack of a measurable Φ ff for Pt etioporphyrin implies a minimum Δ ν ∼ > 5 cm −1 . In n-alkane matrices the absorption S 0 → S 1 shows quasilines with halfwidths Δ ν ∼ ∼ 8 cm −1 , 16 cm −1, and 140 cm −1 for Pd, Pt, and Cu porphin, respectively. The experimental values for the latter two are attributed to uncertainty broadening arising from radiationless decay out of S 1.