Alkyne-Functionalized Zirconocene Complexes: Synthesis, Structures, and Reactivities

Abstract

Reactions of (phenylethynyl)lithium with substituted cyclopentenones gave the corresponding phenylethynyl-substituted cyclopentadienes 1,2-R2-4-(PhCC)C5H2 (R = Me (1a), Ph (1b)), which underwent subsequent deprotonation and transmetalation with ZrCl4 to yield the corresponding alkyne-functionalized zirconocene complexes {η5-[1,2-R2-4-(PhCC)C5H2]}2ZrCl2 (R = Me (2a), Ph (2b)). Thermal treatment of 2a,b with Ru3(CO)12 in refluxing benzene afforded the trinuclear complexes (3,4-R2C5H2)2(μ3-C4Ph2)Ru3(CO)6(μ-CO)2 (R = Me (3a), Ph (3b)) and the dinuclear complex (3,4-Ph2C5H2)2(μ-C4Ph2)Ru2(CO)5(μ-CO) (3c), via the unexpected cleavage of the two Cp′−Zr bonds. The crystal structures of 2b and 3a,c were determined by X-ray diffraction.

Reaction of FcCCC(O)R (Fc = ferrocenyl) with Ru3(CO)12 leading to unexpected nitro-group reduced ruthenoles and 1,2-CO-inserted triruthenium clusters

“… 12 M. Li reported the trinuclear complexes (3,4-R 2 C 5 H 2 ) 2 (μ 3 -C 4 Ph 2 ) Ru 3 (CO) 6 (μ-CO) 2 (R = Me, Ph) and the dinuclear complex (3,4-Ph 2 C 5 H 2 ) 2 (μ-C 4 Ph 2 )Ru 2 (CO) 5 (μ-CO) by reaction of Ru 3 (CO) 12 with {η 5 -[1,2-R 2 -4-(PhC C)C 5 H 2 ]} 2 ZrCl 2 (R = Me, Ph), via the unexpected cleavage of the two Cp–Zr bonds. 13 Recently, P. Mathur reported a series of [Ru(CO) 3 (η 4 -ruthenole)] derivatives during the reaction of Ru 3 (CO) 12 with FcC 2 C 2 Ph (Fc = ferrocenyl). 14 Therefore, the reactions of Ru 3 (CO) 12 with different acetylenes can afford a variety of unexpected products, 10–15 which motivates us to explore the activated mechanisms via experienced sophisticated transformations of alkynes.…”