Reactions of [(CO)3Mn(η5-Thi)]+(Thi = Thiophene or 2,5-Dimethylthiophene) with Nucleophiles

The η 5 -thiophene complexes, [(CO) 3 Mn(η 5 -T)] + ( 1 ) and [(CO) 3 Mn(η 5 -2,5-Me 2 T)] + ( 2 ), react with LiCuR 2 (R = Me or Ph) by adding R - to the sulfur atom of the thiophene, which gives the η 4 -thiophene complexes, (CO) 3 Mn(η 4 -T·R) and (CO) 3 Mn(η 4 -2,5-Me 2 T·R). An X-ray study of (CO) 3 Mn(η 4 -T·C 6 H 5 ) ( 6 ) shows the η 4 -T·C 6 H 5 ligand to be coordinated to the manganese through the four thiophene carbon atoms, while the sulfur bearing the phenyl group is bent away from the metal. The structure of 6 supports previous suggestions that the sulfur in η 5 -thiophene complexes is an electrophilic center. Reactions of 1 or 2 with RS -, CH 3 O -, or - CH(CO 2 CH 3 ) 2 nucleophiles result in the displacement of thiophene with the formation of [(CO) 4 Mn(μ-SR)] 2 or Mn 2 (CO) 10 . The structure of [(CO) 4 Mn(μ-SC 6 H 4 CH 3 - p )] 2 ( 9 ), established by X-ray studies, is also reported.