Crystal Structures of Unusual Titanocene By-products from Attempted Dimerization of Terminal Alkynes

Abstract

Structures of unusual organometallic products μ-[(1,2,3,3a,7a-η):(3a,4,5,6,7,7a-η)-4,7- bis(trimethylsilyl)indenyl]-di-μ-hydridobis(η5-cyclopentadienyl)titanium(TiIII/TiII) (9) and μ-[(3,4,5-η):(4,5,6-η)-(E,E)-2,2,7,7-tetramethylocta-3,5-diene}bis{bis(η5-methylcyclopentadienyl)titanium} (10a) were determined by X-ray diffraction analysis. Compounds 9 and 10a arose as by-products in very low yields in the Ti(C5H5)2(η2-Me3SiC≡CSiMe3)-HC≡CSiMe3 and Ti(C5H4Me)2(η2-Me3SiC≡CSiMe3)-HC≡CCMe3 systems, respectively, when exposed to sunlight. Mechanisms of their formation were tentatively discussed.