Abstract
Reaction of Cp*2VI (Cp* = η5-C5(CH3)5) with NO gave (C5(CH3)5)2VI(NO), a 19-electron complex showing a single ν(NO) absorption band at 1710 cm-1and a 24-line ESR spectrum. The complex is believed to have a linear {VNO} group and planar but displaced C5(CH3)5 rings. The reaction between Cp*2VBr2 and NO gave the salt [Cp*2VBr(NO)][Cp*VBr2(NO)] which was characterized by X-ray diffraction. The cation is diamagnetic (18 electrons) with ν(NO) at 1755 cm-1; the 16-electron anion has ν(NO) at 1715 cm-1, a magnetic moment of 2.55 μB and an eight-line ESR spectrum with Aiso = 71.35 G, showing that the two unpaired electrons are localized on the vanadium atom. Only two electrons take part in V-NO π-bonding; therefore the ν(NO) frequencies and the VNO structural parameters are very similar in the cation and anion (V-N = 1.746 (16) and 1.741 (17) Å, N-O = 1.165 (23) and 1.134 (21) Å, and V-N-O = 175.0 (1.4) and 165.6 (1.8)°, respectively). The V-Br and V-Cp* distances are longer in the cation than in the anion (V-Br = 2.559 (3) vs. 2.483 (5) and 2.441 (4) Å and V-Cp* = 2.005 and 2.020 vs. 1.972 Å, respectively). The nitrosyls described were thermally unstable in solution; above -30 °C they gave green compounds which showed no ν(NO) absorption bands.
Original language | English |
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Pages (from-to) | 961-965 |
Number of pages | 5 |
Journal | Organometallics |
Volume | 4 |
Issue number | 6 |
DOIs | |
Publication status | Published - Jun 1985 |
Externally published | Yes |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry