Stepwise Syntheses of Bisporphyrins, Bischlorins, and Biscorroles, and of Porphyrin−Chlorin and Porphyrin−Corrole Heterodimers

Abstract

The stepwise syntheses and characterization of a series of symmetrical and unsymmetrical bisporphyrins, bischlorins, and biscorroles, and of porphyrin−chlorin and porphyrin−corrole dyads possessing ethylene, phenyl, and stilbene linking units are described. The methodology for synthesis of 10-substituted corroles 2 and their cobalt complexes 9 via a,c-biladiene salts 1 was first developed, and then extended to provide biscorroles (e.g., 4 and 5) linked through the 10-positions with phenyl linker units. Using a similar methodology, phenyl-linked corrole−porphyrin dyads 28 and 30 were also prepared. By way of intermediate phenyl-linked unsymmetrical bisdipyrromethanes, a completely unsymmetrical heterobimetallic bisporphyrin system, 45, was synthesized. Low-valent titanium coupling (McMurry) reactions were used to prepared stilbene-linked bisdipyrromethanes (e.g., 46) which were subsequently transformed into stilbene-linked bisporphyrins (e.g., 48). McMurry cross-coupling reactions of porphyrins bearing p-formylphenyl substituents also afforded an unsymmetrically substituted bisporphyrinylstilbene, 60, as well as the corresponding homodimers 56 and 59. Likewise, McMurry cross-coupling of a p-formylphenyl-substituted porphyrin, 62, with a formylchlorin, 63, afforded a stilbene-linked bisporphyrin, 64, a bischlorin, 66, and a novel porphyrin−chlorin heterodimer, 65. All novel products were characterized by 1H NMR, UV−vis, and mass spectroscopy and elemental analysis. X-ray structural information was also obtained for the zinc/nickel bisporphyrin 45 and for the bis-nickel porphyrin−chlorin 65.

Photophysical Behaviour of Corrole and its Symmetrical and Unsymmetrical Dyads

“…In the last few years we have been interested in the synthesis and characterization of dyads where two different tetrapyrrolic macrocycles are covalently linked [15][16][17][18]. Porphyrin dimers have been extensively used as models of photosynthetic systems and have afforded useful information on the factors influencing elementary photosynthetic processes [19,20].…”

“…As part of these studies we have reported our results on the synthesis and characterization of 1-[5-(10,15,20-triphenylporphyrinyl)]-3-[10-(2,18-diethyl-3,7,8,12,13,17-hexamethylporphyrinyl)] benzene (TPP-DEHMP) dyads [17], and we demonstrated that whereas electronic communications are negligible, as evidenced by electrochemical studies of these compounds, there exists a unidirectional energy transfer process between the TPP and DEHMP subunits. Recently we have also reported the synthesis of some symmetrical and unsymmetrical dyads of corrole [15]; because of the peculiar electronic properties of corrole, studies of these compounds can be particularly interesting.…”

61 The Structural Chemistry of Isolated Chlorophylls

“…121 A dimeric structure consisting of a chlorin e 6 derivative with an appended etioporphyrin unit was reported as well. 122 Rhodochlorin XV dimethyl ester 44 presents an interesting case as two different crystal forms were found. 123 They form different crystal packing arrangements and overall both show only small deviations from Δ24.…”

β,meso‐Acetylenyl‐Bridged, Asymmetrical, Porphyrin Dyads – Synthesis, Spectral, Electrochemical and Computational Studies

“…The crude compound was subjected to silica gel column chromatography using petroleum ether/CH 2 7, 110.2, 114.0, 128.4, 128.5, 134.3, 134.7, 135.2, 135.9, 136.1, 136.3, 138.1, 138.4, 145.8, 148.3, 148.7, 156.8, 157.1, 157.3 C 72.67, H 4.31, N 4.13; found C 72.75, H 4.25, N 4.26. Bromo-10,15,20-tri(p-tolyl)-21,23-dithiaporphyrin (15): Compound 15 was prepared under similar reaction conditions as described above for 14 by treating 10,15,20-tri(p-tolyl)-21,23-dithiaporphyrin (19, 55.0 mg, 0.0901 mmol) in CHCl 3 (15 mL) at room temperature with NBS (16.0 mg, 0.0901 mmol) at room temperature for 10 min.…”

“…Asymmetrical porphyrin dyads containing different macrocycles such as porphyrin-phthalocyanine, [1] porphyrin-chlorin, [2] porphyrin-corrole [3] and porphyrin-heteroporphyrin [4] have receiving attention recently, because the singlet-state energy levels of two macrocycles in these types of dyads are arranged favorably for efficient transfer of energy in the metal-free state. Earlier reports on covalently linked porphyrin dyads were mainly limited to systems containing two of the same type of macrocycles such as two normal porphyrins (N 4 core).…”