Synthesis, structure, and olefin polymerization with nickel(ii) N-heterocyclic carbene enolates

Abstract

Two novel N-heterocylic carbene enolate nickel complexes have been prepared and shown to be active for ethylene and propylene polymerization to yield linear polymers.

Nickel N-heterocyclic carbene complexes and their utility in homogeneous catalysis

“…The following nickel complexes (581), [179] (589−590) [197] and (677) [204] effectively polymerized ethylene. The complexes (589−590) [197] produced polypropylene in the absence of any co-catalyst.…”

“…In particular, the (533−534), [163] (535), [164] (536), [165] (543−544), [166] (545−546), [167] (548 [168]−557), [169] (558), [51] (559), [71] (560), [161] (561), [170] (562−563), [141] (565), [171] (566−567), [172] (568), [173] (569), [126d] (570−573), [174] (574), [175] (575−576), [176] (577), [177] (578), [178] (579), [106] (580−581), [179] (582−583), [151] (584−585), [180] (586−588), [181] (595−596), [182] (597−599), [183] (600−603), [184] (604), [185] (605−608), [186] (609), [185] (610−613), [187] (614−618), [188] (619−621), [189] (622−623), [185] (624−630), [190] (631), [191] (633−635), [192] (636), [193] (637), [194] (647) [195] and (648) [196] complexes were obtained by this pathway from the treatment of the free or the in situ generated NHC The third route is the oxidation method (Scheme 15) using which the (589−590), [197] (638) …”

Olefin Polymerization with Non-metallocene Catalysts (Late Transition Metals)

“…Waymouth reported Ni complex with Nheterocyclic carbene enolate ligand (9d) acts as a single component catalyst for ethylene polymerization [157]. The activity is low to moderate to yield the linear polymer with molecular weight M n ranging from 1,000 to 7,100.…”

Donor‐Functionalised N‐Heterocyclic Carbene Complexes of Group 9 and 10 Metals in Catalysis: Trends and Directions

“…Toluene solutions of the neutral Ni II complex 71, containing a novel anionic NHC-enolate ligand formed single component catalysts (no cocatalyst necessary) for the polymerisation of ethylene to linear polyethylene, with high α-olefin end groups. [115] However, the catalysts were short-lived, and a possible decomposition mecha-nism was proposed, involving chain-transfer by β-elimination, generating a carbene-Ni-H intermediate, which decomposed by reductive elimination. In related studies, Ni IIallyl complexes of NHC-enolate ligands were prepared and tested in ethylene polymerisation.…”