Copolymerization of Ethylene with Cyclohexene (CHE) Catalyzed byNonbridgedHalf-Titanocenes Containing Aryloxo Ligand:  Notable Effect of Both Cyclopentadienyl and Anionic Donor Ligand for Efficient CHE Incorporation

Abstract

Cyclohexene (CHE) has been incorporated into the polymer chain in ethylene/CHE copolymerization by nonbridged half-titanocenes containing aryloxo ligands of the type, Cp'TiCl2(O-2,6-iPr2C6H3), in the presence of methylaluminoxane (MAO) cocatalyst. The effect of the substituent in the cyclopentadienyl fragment was found to be very important for CHE incorporation; both the tert-BuCp (3) and 1,2,4-Me3Cp analogues (4) showed efficient CHE incorporation, whereas a negligible amount of CHE incorporation was observed by both the indenyl (1) and the Cp* analogue (2) under the same conditions. Cp-ketimide analogue, CpTiCl2(N=CtBu2) (5), zirconocene-like Cp2ZrCl2 (6), and linked half-titanocene-like [Me2Si(C5Me4)(NtBu)]TiCl2 (7) did not show any CHE incorporation under the same conditions; unique characteristics for using this type of catalyst precursor for the present copolymerization have thus been emphasized.

Design of Efficient Molecular Catalysts for Synthesis of Cyclic Olefin Copolymers (COC) by Copolymerization of Ethylene and α-Olefins with Norbornene or Tetracyclododecene

“…; Y = anionic ancillary donor such as aryloxy, ketimide, imidazolin-2-iminato, etc. )-that efficient catalysts for the desired copolymerization can be tuned by the ligand modification on both the cyclopentadienyl fragment and nature (and substituents) of the anionic donor ligand employed, as demonstrated in the ethylene copolymerization with NBE [22][23][24], TCD [53], cyclohexene [72], cyclopentene [73], 2-methyl-1-pentene [74], and the others [39,41,45], as summarized in Scheme 6. We thus believe that the results demonstrated here are promising in terms of the synthesis of new polymers, and provides a better understanding not only for the polymer design (combination of monomers), but also for the catalyst design for efficient synthesis.…”

Stereo-controlled synthesis of polyolefins with cycloalkane groups by using late transition metals

“…25 Compared with the corresponding homopolymers, the copolymerization of cyclic alkenes with ethylene or a-olefins produces polymers with cycloalkane groups in a relatively low density. [26][27][28][29][30][31][32][33][34] The average density of cyclic units along the polymer chain can be controlled by changing the molar ratio of monomers, and the polymer properties also vary accordingly. However, the accurate control of the distribution of cyclic units in the polymer chain has not been achieved.…”

Styrene polymerization by nickel and titanium catalysts based on tris(pyrazolyl)borate ligands

“…This can be explained by the fact that the average molecular weights are mainly determined by the k p /k tr ratio, where k tr increases with temperature faster than k p with the following decrease of M w with increasing temperature. does not provide significant influence on the coordination of styrene to the titanium metal center as observed for the nickel pre-catalysts (1)(2). In both cases, very low styrene conversion have been obtained reaching no more than 2% of the total amount of styrene in the polymerization medium.…”

“…1 Many contributions have thus been made concerning this topic, especially using Group 4 and Group 10 metals for polymerization of ethylene, 2 propylene, 3 and in copolymerization reactions. 4 Among linear α-olefins, special attention has been devoted to the use of styrene as monomer for production of polystyrene considering their interesting chemical and physical properties for industrial applications.…”