The Titanocene Complex of Bis(trimethylsilyl)acetylene:  Synthesis, Structure, and Chemistry

Abstract

From a historical point of view “From Silicon to Titanium and Back to Silicon”, the genesis of the titanocene complex of bis(trimethylsilyl)acetylene (1) is explained. Similarities to the known 1-silacyclopropenes led us to describe the bonding in 1 in terms of a 1-titanacyclopropene. Complex 1 is a useful source of the highly reactive bis(cyclopentadienyl)titanium(II), which undergoes both stoichiometric and catalytic reactions that bear a striking similarity to some of the reactions of the isolobal silicon analogues.

Nitril‐Nitril‐C‐C‐Kupplungen an Gruppe‐4‐Metallocenen zu 1‐Metalla‐2,5‐diazacyclopenta‐2,4‐dienen und deren Reaktionen

“…Bei einem Überschuss des Alkins kçnnen durch die Kupplung von zwei Substraten 1-Metallacyclopenta-2,4-diene gebildet werden. [2] Diese Ergebnisse veranlassten uns, die Bildung der Heterometallacyclen, [3] der entsprechenden 1-Metalla-2,5-diazacyclopenta-2,4-diene, durch die Kupplung von zwei Nitrilen zu untersuchen. Nitrile sind für die Entwicklung neuer Synthesestrategien von ganz besonderem Interesse, da sie sehr gebräuchlich und vielseitig sind.…”

“…Synthese der 1-Titana-2,5-diazacyclopenta-2,4-diene (* = Ausbeute NMR-spektroskopisch bestimmt). 108.9(2) 111.6 (2) . und für die Reaktion von 1-Zr zu 2 a-Zr À21.8 kcal mol À1 .…”

Reactions of Titanocene- and Zirconocene-Bis(trimethylsilyl)acetylene Complexes with Selected Heterocyclic and Aromatic NH and OH Acid Compounds

“…In reactions of different titanocene and zirconocene complexes of bis(trimethylsilyl)acetylene Cp 2 M(L)(η 2 -Me 3 SiC 2 SiMe 3 ) (M = Ti, L = nil (1); M = Zr, L = THF (3)), and the pentamethylcyclopentadienyl complexes Cp* 2 M(η 2 -Me 3 SiC 2 SiMe 3 ) (M = Ti (2), Zr (4)) or the rac-ethylenebistetrahydroindenyl (ebthi) complex rac-(ebthi)M(η 2 -Me 3 SiC 2 SiMe 3 ) (M = Zr (5)), activation of several bonds was described in some reviews [1][2][3][4][5][6][7][8][9][10] . For example, cleavage of C-H, C-C (Cp-ring opening, cleavage of butadiynes), Si-C, P-C, N-H, N-C, N-N, Si-O, N-O, C-O, C-S, C-F and C-B bonds gave complexes of potential applicability in stoichiometric and catalytic reactions.…”

Directed Reduction of Six‐Membered Nitrogen Heterocycles—Selective Formation of Polynuclear Titanium Complexes

“…[7b, 8] Here we report on the reaction of titanocene precursors with six-membered N-heterocycles which leads, by way of selective C À C coupling, to the formation of polynuclear titanium compounds. Reaction of the titanocene complexes [Cp 2 Ti{h 2 -C 2 (SiMe 3 ) 2 }] (1) and [Cp * 2 Ti{h 2 -C 2 (SiMe 3 ) 2 }] (2) [8] with triazine (3) at 25 (1) or 608C (2), respectively, led, after 48 h, to the dinuclear chelate complexes 4 or 5, respectively, which can be isolated in 45 % or 32 %, respectively (Scheme 1).…”

“…Reaction of the titanocene complexes [Cp 2 Ti{h 2 -C 2 (SiMe 3 ) 2 }] (1) and [Cp * 2 Ti{h 2 -C 2 (SiMe 3 ) 2 }] (2) [8] with triazine (3) at 25 (1) or 608C (2), respectively, led, after 48 h, to the dinuclear chelate complexes 4 or 5, respectively, which can be isolated in 45 % or 32 %, respectively (Scheme 1). Complexes 4 and 5 are sparingly soluble in aliphatic and aromatic hydrocarbons as well as in THF and decompose above 300 8C, without melting.…”