title: 1,3-Butadienyl Dianions as Non-Innocent Ligands: Synthesis and Characterization of Aromatic Dilithio Rhodacycles.
abstract: Herein we report that 1,4-dilithio-1,3-butadienes, a type of 1,3-butadienyl dianion, can act as non-innocent ligands, taking electrons from low-valent transition metals. Dilithio reagents reacted with [{RhCl(cod)}2] to give dilithio rhodacycle 3 a. Single-crystal X-ray structural analysis revealed the structure of 3 a with averaged bond lengths. XPS data suggested that the oxidation state of Rh in 3 a was more likely to be Rh(3+). CDA/ECDA confirmed the electron-transfer process. (7)Li NMR spectra of 3 a and theoretical calculations revealed a considerable aromatic character. In this process, the dilithio compounds behaved as non-innocent ligands and formal oxidants. These results demonstrated that organolithium compounds with suitable π-conjugation could be used as electron acceptor.
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.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: Yongliang
authors.initials: Y
authors.lastname: Zhang
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: Wen-Xiong
authors.initials: WX
authors.lastname: Zhang
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). zfxi@pku.edu.cn.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Xi
keywords: dianions; lithium; metallacycles; redox reaction; rhodium