Iron complexes phenoxy

Terminally brominated PE as PE macroinitiator can be produced by other methods. It has been reported that vinyl terminated PE produced by a bis(phenoxy-imine)metal complex and MAO catalyst system (Mn = 1800, Mw/Mn = 1.70) was converted to terminally 2-bromoisobutyrate PE through the addition reaction of 2-bromoisobutyric acid to the vinyl chain end. Polyethylene-Wodc-poly( -bulyl acrylate) (PE-fo-PnBA) from terminally brominated PE by ATRP procedure has also been produced [68]. It was reported that degenerative transfer coordination polymerization with an iron complex can be used to prepare terminally brominated PE as a macroinitiator [69]. A Zn-terminated PE prepared using an iron complex and diethylzinc,... 

The homoleptic iron(II) phenoxy functionalised carbene complex was used in the ROP of e-caprolactone [64]. The polymerisation proceeds via a coordination-insertion mechanism [65-67] and the final product has the functionalised imidazolium unit as end group. Performance was riddled by poor control over number-average molecular weight and decreasing molecular weight with decreasing feedstock levels. This was attributed to inter-and/or intramolecular transesteriflcation processes [65,66],... 

Shen and coworkers used Kawaguchi s phenoxy functionalised carbene ligand for the preparation of nickel(II) [62] and iron (II) [63] carbene complexes. Using the same deprotonation method — NaN(SiMe3)2— they attempted the synthesis of a mono-carbene nickel(II) complex that resulted in the formation of the homoleptic complex instead [62] (see Figure 4.16). Use of the correct stoichiometries significantly increased the yield. 

Figure 4.17 Synthesis of a homoleptic iron(ll) carbene complex with a phenoxy functionalised NHC ligand.

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