Serendipity in unexpected reactions of group 4 metallocene Bis(trimethylsilyl)acetylene complexes and its consequences for selected applications

Publication date: Available online 9 December 2019Source: Journal of Organometallic ChemistryAuthor(s): U. RosenthalAbstractExamples for serendipity in several unexpected reactions of group 4 metallocene bis(trimethylsilyl)acetylene complexes are summarized in this Review. The first is the reaction of Cp2Ti (η2-btmsa) with tolane, PhC≡CPh, investigated 1988 in the Nesmeyanov Institute in Moscow giving surprisingly no coupling of Me3SiC≡CSiMe3 with PhC≡CPh to a titanacyclopentadiene but the substitution of bis(trimethylsilyl)acetylene by tolane and via the assumed alkyne complex Cp2Ti (η2-PhC2Ph) a C–C coupling reaction of two molecules of tolane to the tetraphenyl substituted titanacyclopentadiene (i). This simple substitution reaction of Cp2Ti (η2-btmsa) and of similar complexes was used for the generation of the very reactive coordinatively and electronically unsaturated complex fragments [Cp’2M]. The reaction of this complex with carbon dioxide gave a coupling with Me3SiC≡CSiMe3 to an unexpected dinuclear complex with relevance to the general mechanism of CO2 coupling reactions (ii). Furthermore it was demonstrated, that the Cp ligands in [Cp2Ti] were not inert, showing a rare type of coupling reaction with alkynes or ring opening reactions together with C–C coupling reactions of diynes (iii). Some other unexpected reactions were found with di- or polyynes. Depending on the ligands L (Cp’ = Cp, Cp* etc.), metals M (M = Ti, Zr, Hf) and the substrate s...
Source: Journal of Organometallic Chemistry - Category: Chemistry Source Type: research
More News: Chemistry