(Pentamethylcyclopentadienyl)titanatrane: A New Class of Catalyst for Syndiospecific Polymerization of Styrene

Abstract

A new type of catalyst for the syndiospecific polymerization of styrene, Cp*Ti(N(CH2CH2O)3) (3), was prepared by either the reaction of triethanolamine with Cp*TiCl3 in the presence of triethylamine or the reaction of (N(CH2CH2O)3)TiCl with LiCp*. The former reaction route is more efficient in terms of yield and easy accessibility of a titanium starting compound. The X-ray analysis reveals that 3 exists in a monomeric form in the solid state and the Ti atom adopts essentially an η5 bonding posture with regard to the Cp* ring and a tetradentate bonding mode with regard to the triethanolateamine ligand via a transannular interaction from the bridgehead N atom to Ti. The compound 3, which is stable to air and heat and soluble in hydrocarbon solvents, shows very efficient catalytic activity for the syndiospecific polymerization of styrene in the presence of modified methylaluminoxane (MMAO) as cocatalyst.

Synthesis of new substituted cyclopentadienyl titanium monomethoxydifluorides with BF3·OEt2 as fluorinating reagent and their use in syndiotactic polymerization of styrene

“…In order to obtain an efficient catalyst system, which should have a high polymerization activity, increase the tacticity, the melting point and the molecular weight of s-PS, and meanwhile decrease the amount of MAO, a wide variety of new catalysts based on titanium, zirconium or other transition metal compounds have been developing [3][4][5]. Among them, half-sandwich titanocenes of types Cp 0 TiX 3 and Ind 0 TiX 3 (where Cp 0 is (un)substituted cyclopentadienyl, Ind 0 is (un)substituted indenyl, and X is Cl, F, Alkyl or alkoxyl, etc.)…”

Synthesis of new titanatranes containing organic substituents in the atrane fragment

“…21-25 A broad range of titan atranes containing various cyclopentadienyl substituents (Cp*, C 5 Me 4 H, C 5 Me 4 Et, C 5 Me 4 Ph и C 5 Me 4 Tol) at the titanium atom and the Ph and Me groups at the carbon atoms of the atrane skeleton have been reported. [26][27][28] The atranes were synthesized by the reaction of the corre sponding trichloro(η 5 2,4 cyclopentadien 1 yl)titanium with trialkanolamine in the presence of Et 3 N. The cata lytic properties of the obtained compounds were studied in styrene polymerization; the structures of six cyclo pentadienyl derivatives were determined by X ray diffrac tion. By the beginning of our study, only one titanatrane containing the unsubstituted cyclopentadienyl ring, N(CH 2 CH 2 O) 3 TiCp, has been described in the literature.…”

Synthesis, X-ray structures, and syndiospecific polymerization behavior of styrene of new (pentamethylcyclopentadientyl) titanatranes containing modified tetradentate triethanolamine ligands

“…space group P2 1 /n, P2 1 /c and Pc, respectively. Like other known pentamethylcyclopentadienyltitanatrane complexes [12,14], the structures reveal that complexes are certainly mononuclear.…”