X-ray and NMR structural studies of the series of porphyrazines with peripheral pyrrolyl groups

The Valence and Spin State Tuning of Iron(II/III) Porphyrazines with Bulky Pyrrolyl Periphery in Solution and Solid State

“…The 1 H and 13 C NMR spectra of synthesized porphyrazines 5a-5c were recorded in deuterated pyridine for better solvation than in CDCl3, resulting in a reduction of the paramagnetic Fe(III) species to the diamagnetic Fe(II) derivative. In the 1 H NMR of 5a, the splitting of CH3 signals from both dimethylamino and 2-methyl-5-phenylpyrrolyl groups can be noticed in the aliphatic area due to atropoisomer formation (see page 18 in Supplementary Materials) observed for the magnesium(II) analog [18]. The occurrence of the 1 H signal splitting of phenyl substituents in the aromatic area in 5b due to atropoisomerism was also recorded.…”

“…Previously, we reported the synthetic pathway and physicochemical characterization of metal-free porphyrazines with an alternate system of 2,3,5-trisubstituted pyrrolyl and dimethylamino substituents [18,22,23]. The Paal-Knorr reaction of diaminomaleonitrile (1) with 1-phenylpentane-1,4-dione in methanol, 1,2,4-triphenylbutane-1,4-dione in methanol, and 2,5-hexanedione in benzene, and in the presence of the catalytic amount of trifluoroacetic acid (TFA) or oxalic acid, led to the maleonitrile derivatives 2a, 2b, and 2c, respectively (Scheme 1).…”

“…Synthesis of 5a, 5b, and 5c may be considered as the continuation and further development of the recently published methodology which allowed the obtaining of magnesium(II) porphyrazine with 2,5-diphenylpyrollyl and dimethylamino groups and its iron(II) analog 5d [18,22].…”

“…It can be noted that the addition of phenyl groups to peripheral pyrrolyl substituents in 5a and 5b led to an increase in the Soret/Q-band ratio compared to 5c with 2,5-dimethylpyrrolyl moieties. Molecules 2022, 27, x FOR PEER REVIEW 3 of 17 Synthesis of 5a, 5b, and 5c may be considered as the continuation and further development of the recently published methodology which allowed the obtaining of magnesium(II) porphyrazine with 2,5-diphenylpyrollyl and dimethylamino groups and its iron(II) analog 5d [18,22].…”

“…Luo et al [16] synthesized binuclear Pzs with twelve peripheral trimethylthiophenyl groups, revealing interesting photochromic characteristics. For the last 15 years, our group obtained many examples of Pzs bearing peripheral 2,5-dimethylpyrrol-1-yl, 2,5dithienylpyrrol-1-yl, 2,5-di(biphenyl-4-yl)pyrrol-1-yl, 2-(1-adamantyl)-5-phenylpyrrol-1-yl, and 3,4-dihalide-2,5-dimethylpyrrol-1-yl moieties [17][18][19][20][21]. Lately, it was found that bulky 2,5-diphenylpyrrol-1-yl substituents on the periphery of iron(II) porphyrazine influence its physicochemical properties, which was confirmed by Mössbauer spectroscopy [22].…”