166905-91-5Relevant academic research and scientific papers
η1-Vinylidene to η2-Alkyne Isomerization of Tungsten and Molybdenum Complexes
Ipaktschi, Junes,Mohsseni-Ala, Javad,Uhlig, Sascha
, p. 4313 - 4320 (2003)
The thermal isomerizations of η1-vinylidene complexes [(η5-C5H5)(CO)(NO)W=C=CHR] [5a, R = Si(CH3)2C(CH3)3; 5c, R = C(CH 3)3] as well as [(η5-C5H 5)(CO)(NO)Mo=C=CHC(CH3)3] (8), to the corresponding η2-1-alkyne complexes [(η5-C 5H5)(CO)(NO)W(η2-H-C≡C-R)] [7a, R = Si(CH3)2C(CH3)3; 7c, R = C(CH 3)3] and [(η5-C5H 5)(CO)(NO)Mo{η2-H-C≡C-CHC(CH3) 3}] (9) has been investigated. Activation parameters for the isomerization of 5a in [D6]benzene and 8 in [D8]toluene and [D5]ethanol were determined. In [D8]toluene η 1-vinylidene complex 5a undergoes a single step 1,2-shift of the silyl group from Cβ to Cαm. However, complex 8 shows dichotomous behavior. The isomerization 8 → 9, dependent upon the solvent applied, occurs by means of two different pathways: in a nonpolar solvent, 8 tautomerizes via the 1,2-migration of the hydrogen atom to 9 and in ethanol this tautomerization proceeds by a multi-step process via deprotonation-protonation and subsequent reductive elimination. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
