6533b82ffe1ef96bd1295a85

RESEARCH PRODUCT

Reactions of titanocene-bis(trimethylsilyl)ethyne complexes with diethynylsilane derivatives

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Titanocene complexes [Ti(η 5 -C 5 H 5− n Me n ) 2 (η 2 -Me 3 SiCCSiMe 3 )] ( n =0, 4 and 5) react uniformly with siladiynes R 2 2 Si(CCR 1 ) 2 , where R 1 =Ph, and R 2 =Ph or Me, at elevated temperature in hydrocarbon solvents to give the corresponding silacyclobutene-annelated titanacyclobutene complexes, 3-bis(η 5 -cyclopentadienyl)titana-6-diorganylsilabicyclo[2.2.0]hexa-1(2),4(5)-dienes, [(η 5 -C 5 H 5− n Me n ) 2 Ti{R 1 2 C 4 (SiR 2 2 )}]. Products arising from [Ti(η 5 -C 5 H 5− n Me n ) 2 (η 2 -Me 3 SiCCSiMe 3 )] ( n =0, 2 (1,3-isomer), 4 and 5) and Me 2 Si(CCCMe 3 ) 2 vary with n : the non-methylated titanocene complex affords a mixture of an analogous silacyclobutene-annelated titanacyclobutene and [{Ti(η 5 -C 5 H 5 ) 2 } 2 {μ-η(3–5):η(4–6)-Me 3 CCCCCCMe 3 }], the permethylated titanocene precursor gives mainly the allyldiene complex [Ti(η 5 -C 5 Me 5 )(η 3 :η 4 -C 5 Me 3 (CH 2 ) 2 )] while no titanium-containing product could be isolated for n= 4. The reaction of [Ti(η 5 -1,3-C 5 H 3 Me 2 ) 2 (η 2 -Me 3 SiCCSiMe 3 )] with Me 2 Si(CCCMe 3 ) 2 , however, cleanly affords the expected silacyclobutene–titanacyclobutene complex. All complexes were studied by spectral methods and solid-state structure of two representatives, [(η 5 -C 5 Me 5 ) 2 Ti{Ph 2 C 4 (SiMe 2 )}] and [(η 5 -1,3-C 5 H 3 Me 2 ) 2 Ti{(Me 3 C) 2 C 4 (SiMe 2 )}] was determined by single-crystal X-ray diffraction.