Synthesis, Structures and Properties of Half-Sandwich Nickel(II) Complexes with Backbone-Modified NHC Ligands
Łukasz Banach , Piotr Guńka , Dominika Górska , Maja Podlewska , Janusz Zachara , Włodzimierz Buchowicz
AbstractA series of seven nickel complexes [Ni(η5-C5H5)(X)(NHC)] (X = Cl or Br; NHC = N-heterocyclic carbene) containing backbone-modified NHC ligands was prepared by treatment of nickelocene with the corresponding NHC·HX salts or, in the case of complex 1h [Ni(η5-C5H5)(Cl)(IMesO)] (IMesO = 4-oxo-1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene), by deprotection of the corresponding NHC ligand in complex 1g [Ni(η5-C5H5)(Cl)(IMesOPiv)] [IMesOPiv = 4-(pivaloyloxy)-1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene]. Single-crystal X-ray structures were determined for complexes 1d [Ni(η5-C5H5)(Cl)(Bn2-bimy)] (Bn2-bimy = 1,3-dibenzylbenzimidazolin-2-ylidene), 1g and 1h. The coordination spheres around the nickel atoms resemble those of d8 NiL4 square-planar complexes, with Ni–C(Cp) bond length differentiation and C–C bond alternation in Cp ligands being taken into account. Desymmetrization of the five-membered heterocyclic ring and a tautomeric equilibrium were observed for complex 1h. All new complexes are efficient precatalysts in three C–C bond-forming reactions (polymerization of styrene, polymerization of methyl methacrylate, Suzuki–Miyaura cross-coupling).
|Journal series||European Journal of Inorganic Chemistry, ISSN 1434-1948 [0009-2940], (A 30 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||Nickel ; N-Heterocyclic carbenes ; C–C coupling ; Polymerization ; Protecting groups|
|Score|| = 35.0, 12-03-2019, ArticleFromJournal|
= 35.0, 12-03-2019, ArticleFromJournal
|Publication indicators||= 14; : 2016 = 0.633; : 2015 = 2.686 (2) - 2015=2.68 (5)|
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