The Mono-, Di-, and Tri([5]trovacenyl)boranes: A Study of Intermetallic Communication Across an sp2-Hybridized Boron Atom
✍ Scribed by Christoph Elschenbroich; Matthias Wolf; Olaf Burghaus; Klaus Harms; Jürgen Pebler
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 666 KB
- Volume
- 1999
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
The paramagnetic complexes di(mesityl) ([5]trovacenyl)-the exchange interaction J in the diradical 6 •• approaches the fast-exchange region and is attenuated significantly by borane (5 • ), (mesityl)di([5]trovacenyl)borane (6 •• ), and tri([5]trovacenyl)borane (7 ••• ) were prepared from quaternization at boron in [6 •• -nBu] -. Although EPR spectroscopy of the triradical 7 ••• also indicates an extensive [5]trovacenyllithium, (η 5 -C 7 H 7 )V(η 5 -C 5 H 4 Li), and (Mes) 2 BF, (Mes)BF 2 , and BF 3 , respectively. The propeller-shaped exchange interaction, the exchange parameters, derived from spectral simulation, follow the gradation J(7 and7 ••• were subjected to X-ray diffraction with the aim of possibly correlating the twist angles with J(6 •• ). The magnetic susceptibility of 6 •• and 7 ••• follows the same trend. As expected, compound 7 ••• exhibits spin intramolecular intermetallic communication. Cyclic voltammetry points to successive vanadium-centered frustration because it contains three antiferromagnetically coupled S = 1/2 systems that are arranged in an equilateral oxidation processes and boron-centered reduction, a small redox splitting δE 1/2 [(2+/+), (+/0)] being observed for 6 •• . triangle. According to EPR spectroscopy, performed in fluid solution, troscopy, which may either be applied to mixed valence
Results and Discussion
intramolecular communication is provided by EPR spec-