title: The C-H bond activation in 1-ethyl-3-methylimidazolium acetate-copper(II) acetate-water-air (dioxygen) systems.
abstract: Ionic liquid (1-ethyl-3-methylimidazolium acetate, [C2C1im][AcO])-copper(ii) diacetate monohydrate-water-air (O2) systems have been investigated by (13)C NMR, EPR, spectrophotometry, HPLC, and synthetic chemistry methods at different temperatures. The C-H bond activation of [C2C1im](+) with the formation of the unusual dication 1,1'-diethyl-3,3'-dimethyl-2,2'-biimidazolium ([(C2C1im)2](2+)) at 50 °C and 1-ethyl-3-methyl-1H-imidazol-2(3H)-one (C2C1imO) at 50-85 °C was revealed. Two new complexes with the above compounds, [(C2C1im)2][Cu(AcO)4] and Cu2(AcO)4(C2C1imO)2, were isolated from the systems and characterized by X-ray structural analysis. Catalytic cycles with the participation of copper(ii) acetate and dioxygen and the production of [(C2C1im)2](2+) and C2C1imO have been proposed. The catalysis presumably includes the formation of the Cu(II)(O2)Cu(II) active centre with μ-η(2):η(2)-peroxide bridging in analogy with tyrosinase and catechol oxidase activity.
authors.affiliation: Kazan Federal University, A. M. Butlerov Chemistry Institute, Kremlevskaya st. 18, 420008, Kazan, Russian Federation. Valery.Shtyrlin@ksu.ru.
authors.forename: Valery G
authors.initials: VG
authors.lastname: Shtyrlin
authors.forename: Nikita Yu
authors.initials: NY
authors.lastname: Serov
authors.forename: Daut R
authors.initials: DR
authors.lastname: Islamov
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Konkin
authors.forename: Mikhail S
authors.initials: MS
authors.lastname: Bukharov
authors.forename: Oleg I
authors.initials: OI
authors.lastname: Gnezdilov
authors.forename: Dmitry B
authors.initials: DB
authors.lastname: Krivolapov
authors.forename: Ol'ga N
authors.initials: ON
authors.lastname: Kataeva
authors.forename: Gulnara A
authors.initials: GA
authors.lastname: Nazmutdinova
authors.forename: Frank
authors.initials: F
authors.lastname: Wendler
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000388:Air; D002244:Carbon / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000085:Acetates; D007093:Imidazoles; D014867:Water; D002244:Carbon; D003300:Copper; D006859:Hydrogen; D010100:Oxygen; C518739:1-ethyl-3-methylimidazolium