Synthesis and Characterization of Nitrogen-Functionalized Cyclopentadienylchromium Complexes and Their Use as Catalysts for Olefin Polymerization

Abstract

A series of nitrogen-functionalized cyclopentadienylchromium complexes (1-9) have been synthesized, characterized, and then tested as catalyst precursors for olefin polymerization. The structures of complexes 1 and 5 show the nitrogen atom coordinated to the chromium atom, which is confirmed by X-ray crystallography. In the presence of MAO, the complexes exhibited high catalytic activities for the homopolymerization of ethylene and its copolymerization with 1-hexene. It also turned out that both the activity of ethylene polymerization and the incorporation of 1-hexene into the copolymer were highly affected by the substituents on the cyclopentadienyl fragment and bridge group. The effects of temperature variation and Al/Cr ratio on catalytic activity were also studied.

Reactions of Pyridyl Side Chain Functionalized Indenes with Ru3(CO)12

“…Reaction of 1 with Ru 3 (CO) 12 in Xylene When 1 [9] was treated with Ru 3 (CO) 12 in refluxing xylene for 5 h, the α-C-H bond of the pyridyl group activated product 8 was obtained in 29 % yield, in addition to the normal diruthenium complex 7 (14 %) (Scheme 1). Although xylene was used as the solvent, no product resulting from the reaction of Ru 3 (CO) 12 with xylene was detected.…”

“…Elemental analyses were performed with a Perkin-Elmer 240C analyzer. Ligand precursors 1, [9] 3, [21] and 6 [17] were synthesized according to literature procedures.…”

“…[9] A solution of 6,6Ј-dimethylbenzofulvene (10.2 g, 65.4 mmol) in Et 2 O (50 mL) was added to a solution prepared from 2,6-dimethylpyridine (7.00 g, 65.4 mmol) in n-hexane (100 mL) and nBuLi (41.5 mL, 50.7 mmol). The mixture was stirred overnight at room temperature and hydrolyzed with water.…”

Cr Complexes of Nitrogen Donor Ligands for Olefin Oligomerisation and Polymerisation

“…Various modifications of this theme have been investigated in the years since. Huang et al prepared and tested complexes of general structure 5 and 6 for ethylene polymerisation in combination with MAO [11]. The effect of different bridge substitution and steric bulk on the Cp group was explored.…”

Synthesis of Novel Trichloride Indenyl Zirconium Complexes with Pendant Pyridine Moiety

“…这种方法适用于环戊二烯或茚基配体上 有较大取代基, 但原料 Zr(NMe 2 ) 4 制备比较困难. [18] . 配体进一步锂化后, 与 1 equiv.的 ZrCl 4 •2THF 反应得到目标产物.…”