Synthesis and properties of 1,2,3-diazapnictol-5-yl substituted ferrocenes
| Autor: | Martin Hejda, Libor Dostál, Tomáš Mikysek, Aleš Růžička, Pavel Kozáček, Milan Erben |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | New Journal of Chemistry. 45:18171-18182 |
| ISSN: | 1369-9261 1144-0546 |
| Popis: | The reaction of acetylferrocene hydrazone or 1,1′-diacetylferrocene dihydrazone with PCl3 gives the corresponding azines as the only organometallic product. The separation of the hydrazone function with a 1,4-phenylene or propane-2,2-diyl spacer enables the preparation of new heterocyclic compounds [(2H-1,2,3-diazaphosphol-5-yl)-4-phenyl]ferrocene (2b) and [1-(2H-1,2,3-diazaphosphol-5-yl)-1-methyl-ethyl]ferrocene (2c) but in low yields. Using acetylated hydrazones, that do not undergo transformation into stable azine molecules, led to the synthesis of (2-acetyl-1,2,3-diazaphosphol-5-yl)ferrocene (5a) and 1,1′-bis(2-acetyl-1,2,3-diazaphosphol-5-yl)ferrocene (8) in up to 70% yield. N-Acylated compounds 5a and 8 are readily converted to (2H-1,2,3-diazaphosphol-5-yl)ferrocene (2a) and 1,1′-bis(2H-1,2,3-diazaphosphol-5-yl)ferrocene (9). Analogous reactions were utilized for the preparation of (2-acetyl-1,2,3-diazarsol-5-yl)ferrocene (10), (2H-1,2,3-diazarsol-5-yl)ferrocene (11), 1,1′-bis(2-acetyl-1,2,3-diazarsol-5-yl)ferrocene (12) and 1,1′-bis(2H-1,2,3-diazarsol-5-yl)ferrocene (13). Electrochemical studies on a series of new ferrocenes showed that the 2H-1,2,3-diazapnictol-5-yl substituent possesses weak electron-withdrawing ability which is enhanced by acetylation in the 2-position of such a heterocycle. We also observed the electroactivity of the 1,2,3-diazapnictolyl substituent as it could be irreversibly reduced at potentials from −1.97 to −2.93 V vs. the Fc0/+ couple. All prepared compounds have been fully characterized using spectroscopic methods and molecular structures of 2a, 2b, 2c, 5a, 8, 9 and 10 are reported. |
| Databáze: | OpenAIRE |
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