Formation of (vinyl-ferrocenyl)stibines involving β-elimination: Hypervalent Sb–N bonding

Unusual syntheses of vinyl substituted ferrocenylstibines viz. diphenyl(2-vinylferrocenyl) stibine (2) and iodo-(N,N-dimethylaminoethylferrocenyl)(2-vinylferrocenyl)stibine (4) involving β-elimination, are reported. Stibines Ph2SbFc (1) or Fc2SbCl (3) containing dimethylaminoethyl-pendant arm on a ferrocenyl ring on reaction with MeI gives vinyl substituted ferrocenylstibines. All the new stibines were characterized by IR, mass, 1H, 13C, COSY, HETCOR NMR spectroscopy. The structures of all of these 1,2-disubstituted ferrocenylstibines were determined by X-ray diffraction analyses. The compounds 3 and 4 show hypervalent bonding between the antimony and nitrogen atoms giving 6 and 5 coordinated antimony, respectively. This is the first report on ferrocenylstibines containing a vinyl group in their framework.