Karaman, Rafik et al. published their research in Journal of Organic Chemistry in 1991 |CAS: 636-73-7

The Article related to porphyrin dimer quadruply bridged conformation, tetrakisbromoethylphenylporphyrin alkylation pyridinesulfonamide, Biomolecules and Their Synthetic Analogs: Corrinoids, Porphyrins, and Bilines and other aspects.Computed Properties of 636-73-7

On May 24, 1991, Karaman, Rafik; Bruice, Thomas C. published an article.Computed Properties of 636-73-7 The title of the article was Synthesis and characterization of the first water-soluble closely interspaced cofacial porphyrin dimer. And the article contained the following:

The only documented example of a quadruply-bridged, closely-interspaced cofacial porphyrin dimer was synthesized by Kagan (1977). The target of this communication is the synthesis and characterization of the first water soluble quadruply-bridged, closely-interspaced cofacial porphyrin I (R = R1). Reaction of meso-tetrakis(3-bromomethylphenyl)porphyrin with m-pyridinesulfonamide provides the closely-interspaced cofacial porphyrin dimer I (R = R2) which on quaternization with MeI provides the water soluble I (R = R1). Reactions of I with Zn(OAc)2 provided the corresponding bis-zinc complexes I. Porphyrins I and their bis-zinc complexes, exist in a closed down conformation with closely approaching porphyrin planes or in an open conformation. It was established, on the basis of 1H-NMR UV/vis, and emission spectrophotometries, and I (R = R2) exists in a closed down conformation in DMSO or acetone and a more open conformation is CHCl3. With zinc complexes of I (or protonated I) the conformation is open regardless of the solvent. The experimental process involved the reaction of Pyridine-3-sulfonic acid(cas: 636-73-7).Computed Properties of 636-73-7

The Article related to porphyrin dimer quadruply bridged conformation, tetrakisbromoethylphenylporphyrin alkylation pyridinesulfonamide, Biomolecules and Their Synthetic Analogs: Corrinoids, Porphyrins, and Bilines and other aspects.Computed Properties of 636-73-7

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem