Different Inertness of Titanocene [Cp <sub>2</sub> Ti] and Decamethyltitanocene [Cp* <sub>2</sub> Ti] in Reactions with <i>N</i> , <i>N</i> ‐Bis(trimethylsilyl)sulfurdiimide – Elimination of Tetramethyl­fulvene and Formation of Half‐Titanocene Complexes
The reaction of the titanocene alkyne complex [Cp*2Ti(η2-Me3SiC2SiMe3)] (1) (Cp* = η5-pentamethylcyclopentadienyl) with N,N-bis(trimethylsilyl)sulfurdiimide (2) results in the formation of 1,2,3,4-tetramethylfulvene (3) as well as three titanium complexes 4, 5 and 6. During the reaction, formal elimination of one Cp* ligand induces a series of C–H and N–S bond activation steps, thus yielding the products. The molecular structures of complex 5 and of the free fulvene were determined by X-ray crystallographic analysis. Evidently, in these reactions [Cp*2Ti] is less stable than [Cp2Ti]; a possible reason was found to be the well-known intramolecular C–H activation yielding the tautomeric tetramethylfulvene hydride species, from which 1,2,3,4-tetramethylfulvene (3) can dissociate.