Synthesis and Crystal Structure of a Cumulenic Quinoidal Porphyrin Dimer with Strong Electronic Absorption in the Infrared

Abstract

Quinoidalization results in amazingly intense near‐IR absorption in 1 (λmax=1080 nm), whereas the shorter dimer 2 (λmax=780 nm) is less conjugated because steric interactions force it into a contorted geometry. The crystal structure of 1 shows that the 62‐atom chromophore is bow‐shaped in the solid state.

One-pot synthesis of nickel porphyrins with 2-pyridine-acetyl substituents: the unexpected Sonogashira cross-coupling products

“…This method has been widely used to synthesize porphyrins with ethyne-linked functional groups [11][12][13][14][15]. Although porphyrins with 2-pyridine-ethynyl substituents were expected to be the products according to the method, we found that nickel porphyrins with 2-pyridine-acetyl substituents were in fact the major products (Fig.…”

Oligoporphyrins with One-and Two-Atom Covalent Bridges: Synthesis and Reactivity, Solid-State, Solution and Electronic Structures, Spectroscopy and Applications

“…80 The IA in this complex, shown in Figure 3b, is ca. 38.6°, but there is very little twist around the bridge (ca.…”

“…coupling with malononitrile anion followed by oxidation with N-iodosuccinimide gave the remarkable cumulenic diporphyrinoid 63, whose crystal structure was determined. 80 Sutton and Boyle employed the simpler Heck/Sonogashira coupling of terminal alkynes with iodoporphyrins to prepare meso-ethynyl porphyrins, and one of these was coupled with a regioisomeric mixture of β-iodotri-t-butylphthalocyaninatozinc(II) to form the first C 2 porphyrin-phthalocyanine dyad 64. 81 Sonogashira coupling was also used by Screen et al in an improved synthesis of 59b, 82 and by Lysenko et al to prepare the analog 65a with p-tolyl substituents.…”

“…The pyridine ligands project on the same side of the molecule and on the "inside" of the fold such that they are positioned relatively close together, although not close enough to influence the structure through py⋅⋅⋅py aryl interactions. 80 The molecule comprises Ni(II) 5,15-DAP with a dithiane ring connected to the 15-C meso position, linked by a C 2 bridge to a second 5,15-DAP containing a 5-coordinate zinc center (apical position occupied by a methanol ligand) and with a cyano group at its 15-C meso position. Interestingly there is very little rotation of the planes of the porphyrins around the alkyne bridge (average C β −C meso ⋅⋅⋅C meso −C β torsion angle 8.2°).…”

“…10 5 M −1 cm −1 ) at 455 nm and 1080 nm. 80 The head-to-tail dimers 13a and 13b comprising NiDAP linked to a diiminoporphodimethene or oxoiminoporphodimethene also show broad NIR bands peaking at 803 nm and 865 nm (ε ca. 1.6 × 10 4 M −1 cm −1 ).…”