title: Dianions as Formal Oxidants: Synthesis and Characterization of Aromatic Dilithionickeloles from 1,4-Dilithio-1,3-butadienes and [Ni(cod)2].
abstract: Organolithium compounds can behave as reductants but never as oxidants in redox reactions. Reported herein is that 1,4-dilithio-1,3-butadienes reacted with [Ni(cod)2] (cod = 1,5-cyclooctadiene) to deliver dilithionickeloles. Single-crystal X-ray structural analysis revealed a coplanar structure of dilithionickeloles with an averaging of bond lengths. XPS data confirmed the oxidation state of Ni in dilithionickeloles was Ni(2+). (7)Li NMR spectra of dilithionickeloles and theoretical calculations revealed a considerable aromatic character. In this redox reaction, the dilithio dianionic compounds behaved as formal oxidants, thus oxidizing Ni(0) into Ni(2+). These results demonstrated that organolithium compounds with π-conjugation could be used as oxidants and could continue to accept extra electrons.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871 (China).
authors.forename: Junnian
authors.initials: J
authors.lastname: Wei
authors.forename: Wen-Xiong
authors.initials: WX
authors.lastname: Zhang
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Xi
mesh_terms: D000838:Anions / Q000737:chemistry; D002070:Butadienes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008094:Lithium / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*
chemical_list: C000604791:1,4-dilithio-1,3-butadiene; D000838:Anions; D002070:Butadienes; D009942:Organometallic Compounds; D016877:Oxidants; C000604792:nickel(1,5-cyclooctadiene)2; D009532:Nickel; D008094:Lithium
keywords: aromaticity; lithium; nickel; oxidation; redox chemistry