Synthesis and characterisation of κ2- N, O-oxazoline-enolate complexes of nickel(ii): explorations in coordination chemistry and metal-mediated polymerisation

Jeanette A Adjei; Alan J Lough; Robert A Gossage

doi:10.1039/c8ra10304f

Synthesis and characterisation of κ²- N, O-oxazoline-enolate complexes of nickel(ii): explorations in coordination chemistry and metal-mediated polymerisation

RSC Adv. 2019 Jan 29;9(7):3956-3964. doi: 10.1039/c8ra10304f. eCollection 2019 Jan 25.

Authors

Jeanette A Adjei¹, Alan J Lough², Robert A Gossage¹

Affiliations

¹ Department of Chemistry & Biology, Ryerson University 350 Victoria Street Toronto ON M5B 2K3 Canada gossage@ryerson.ca.
² Department of Chemistry, University of Toronto 80 St. George Street Toronto ON M5S 3H6 Canada alough@chem.utoronto.ca.

Abstract

The synthesis and characterisation (UV-Vis, IR, X-ray diffraction, etc.) of a series of Ni(ii) complexes derived from both known and novel 2-acylmethyl-2-oxazolines (2a-g: i.e., (Z)-1-R-2-(4,4'-dimethyl-2'-oxazolin-2'-yl)eth-1-en-1-ol; R = -Ph, -2-furanyl, -p-NO₂-Ph, -t-Bu, -2-thiofuranyl, p-NC-Ph, -CF₃) is reported. These Ni materials (3a-g) represent the first group 10 metal complexes of this ligand class. All derivatives reported are paramagnetic (S = 1) compounds of formulae Ni(κ²-N,O-L)₂ where L represents an enolate of structure (Z)-1-R-2-(4',4'-dimethyl-2'-oxazolin-2'-yl)eth-1-en-1-ate formed via proton loss from 2. The air- and moisture-stable metal complexes feature a less typical distorted seesaw-shaped disposition of binding atoms around the metal centre for six structurally characterised (X-ray) examples. Preliminary investigations indicate that 3a (R = -Ph) is a useful catalysts for olefin polymerisation in the presence of alkylaluminum reagents.