[5]Trovacenyl Boronic Acid, (η7-C7H7)V[η5-C5H4B(OH)2], and Its Anhydride Tri([5]trovacenyl)boroxine, 1,3,5-[(η7-C7H7)V(η5-C5H4)]3B3O3 ,1
Autor: | Jürgen Pebler, Klaus Harms, Matthias Wolf, Christoph Elschenbroich |
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Rok vydání: | 2003 |
Předmět: | |
Zdroj: | Organometallics. 23:454-459 |
ISSN: | 1520-6041 0276-7333 |
Popis: | The paramagnetic boronic acid (η7-C7H7)V[η5-C5H4B(OH)2] (3•) has been prepared and characterized structurally, emphasis being placed on hydrogen bonding motives present in the crystal. EPR spectroscopy reveals that association of 3• is absent in fluid solution. Tri([5]trovacenyl)boroxine, 4•••, the cyclic anhydride of 3•, engages in antiferromagnetic exchange; magnetic susceptometry provides the value J(4•••) = −1.04 cm-1. Accordingly, the EPR spectrum of 4••• in fluid solution points to 22 51V hyperfine components separated by one-third of the coupling constant of mononuclear trovacene derivatives. Redox splittings δE1/2 between consecutive oxidation steps of 4••• are not resolved, i.e., δE1/2 ≤ 60 mV. |
Databáze: | OpenAIRE |
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