Synthesis, Structure and Solution Studies on Mixed Aryl/Alkyl Lithium Zincates. Issue 29 (22nd September 2016)

• Record Type: Journal Article
• Authors: Roberts, Andrew J.; Kennedy, Alan R.; McLellan, Ross; Robertson, Stuart D.; Hevia, Eva
• Is Part Of: European journal of inorganic chemistry. Issue 29(2016)
• Page Start: 4752
• Page End: 4760
• Publication Date: 2016-09-22
• Subjects: Zincates -- Lithium -- Solvent effects -- Bimetallic chemistry -- Cocomplexation; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201601020
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Novel homo‐ and heteroleptic lithium zincates have been prepared by cocomplexation reactions of Zn(CH2 SiMe3 )2 and PhLi in low‐polarity hydrocarbon solvents. X‐ray crystallographic studies of products obtained by reacting the organometallic reagents in benzene or toluene yield the novel solvent‐free solid‐state arrangement [Li4 Zn3 Ph5 (CH2 SiMe3 )5 ]⋡ (1 ). Combining Zn(CH2 SiMe3 )2 and PhLi in hexane in the presence of the polydentate N‐donors PMDETA ( N, N, N′, N′′, N′′ ‐pentamethyldiethylenetriamine) or TMEDA ( N, N, N′, N′ ‐tetramethylethylenediamine) reveals monomeric heteroleptic [(PMDETA)LiZn(CH2 SiMe3 )2 Ph] (2 ) and homoleptic [(TMEDA)LiZn(CH2 SiMe3 )3 ] (3 ), the result of a disproportionation process, respectively. NMR spectroscopic studies suggest that2 and3 retain their discrete contacted ion‐pair solid‐state structures in benzene solution. Variable‐temperature NMR spectroscopic studies of2 in [D8 ]THF reveal a complex equilibrium also including [LiZn(CH2 SiMe3 )3 ], [LiZn(CH2 SiMe3 )Ph2 ] and [LiZnPh3 ], an equilibrium process analogous to that of1 in THF. This study further highlights the complexity of these reactions, which at first would appear simple. Abstract : Studies on the cocomplexation of PhLi and Zn(CH2 SiMe3 )2 have revealed a dramatic solvent effect and intricate solution behaviours as well as unique structural motifs in zincate chemistry.