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Revisiting the Schlenk Dimerisation Reaction of 1,1-Diphenylethene

Lookup NU author(s): Dr Mo Liu, Dr Ahmed Alwaaly, Dr Paul Waddell, Dr Keith Izod



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


The reaction between 1,1-diphenylethene and two equivalents of lithium in THF gave the complex [(Ph2CCH2CH2CPh2)Li2(THF)4] (3), which crystallised from Et2O/THF as the dialkyllithate salt [Li(THF)4][(Ph2CCH2CH2CPh2)Li(THF)] (3a). A similar reaction between 1,1-diphenylethene and sodium metal in THF gave [(Ph2CCH2CH2CPh2)Na2(THF)1.5] (4), which crystallised from THF as the polymer [(Ph2CCH2CH2CPh2)Na2(THF)3]¥ (4a). In contrast, reactions between 1,1-diphenylethene and potassium under the same conditions gave intractable mixtures of products. However, treatment of 3 with two equivalents of KOtBu in THF yielded the complex [(Ph2CCH2CH2CPh2)K2(THF)0.5] (5) as a deep red powder; treatment of 5 with two equivalents of 12-crown-4, followed by crystallisation from methylcyclohexane/THF, gave the adduct [(Ph2CCH2CH2CPh2)K2(THF)2(12-crown-4)2] (5a). A similar reaction between 3 and 12-crown-4 gave the separated ion pair [Li(THF)(12-crown-4)][Li(THF)0.5(OEt2)0.5(12-crown-4)][(Ph2CCH2CH2CPh2)] (3b), which contains the free 1,1,4,4-tetraphenyl-1,4-butanediide dicarbanion. X-ray crystallography revealed that the C3C centres of the ligands adopt a near planar geometry, irrespective of whether a metal cation is in close contact.

Publication metadata

Author(s): Liu M, Alwaaly A, Waddell PG, Izod K

Publication type: Article

Publication status: Published

Journal: Journal of Organometallic Chemistry

Year: 2023

Volume: 1001

Print publication date: 15/11/2023

Online publication date: 19/08/2023

Acceptance date: 17/08/2023

Date deposited: 07/09/2023

ISSN (print): 0022-328X

ISSN (electronic): 1872-8561

Publisher: Elsevier BV


DOI: 10.1016/j.jorganchem.2023.122865


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Funder referenceFunder name
Ministry of Higher Education and Scientific Research, Iraq