The organothio-bridged derivatives of iron carbonyl. II. The dynamic nuclear magnetic resonance study of the anti-syn isomerism in bis(μ-tertiarybutylsulphido)hexacarbonyldiiron and its monosubstituted products with some phosphines and phosphites: an unusually fast interconversion rate
✍ Scribed by G. Natile; L. Maresca; G. Borb
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- English
- Weight
- 567 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0020-1693
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✦ Synopsis
The anti-syn interconversion rate of (p-Buts),-Fe,(CO), is about one thousand times faster than that of the other alkyl and aryl derivatives and becomes fast in the NMR time scale at temperatures above 90 'C. The coalescence temperature of the But signals is lowered by substitution of a carbonyl group with a phosphorus ligand and a single sharp resonance is observed at room temperature with the more basic phosphines. The mechanism of inversion at sulphur is discussed in connection with related systems. Not all monosubstituted products are stable in solution and their tendency to release the coordinated phosphine increases with the bulkiness of the ligand.