A Tris(trifluoromethyl)antimony Adduct of a Nucleophilic Carbene: Geometric Distortions in Carbene Adducts

✍ Scribed by Anthony J. Arduengo; III; Roland Krafczyk; Reinhard Schmutzler; Walter Mahler; William J. Marshall

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: German
• Weight: 133 KB
• Volume: 625
• Category: Article
• ISSN: 0372-7874
• DOI: 10.1002/(sici)1521-3749(199911)625:11<1813::aid-zaac1813>3.0.co;2-c

✦ Synopsis

The synthesis, characterization and solid state structure are described for a reversed ylide, derived from 1,3-dimesityl-4,5-dichloroimidazol-2-ylidene and tris(trifluoromethyl)antimony. This carbene ´stibine adduct is the first example of the 10-Sb-4 bonding arrangement in which only carbons are bound to antimony. The adduct has an Sb±C (carbene) bond length of 282.1 pm, and a remarkable offset (19°) of the Sb±C (carbene) bond from the pseudo-C 2 axis which passes through the imidazole fragment. A rather weak antimony-carbene interaction is suggested by this geometric distortion and is further supported by variable temperature 19 F NMR experiments and solvent dependencies of chemical shifts.