TY - JOUR
T1 - Synthesis, structure and solution studies on mixed aryl/alkyl lithium zincates
AU - Roberts, Andrew J.
AU - Kennedy, Alan R.
AU - McLellan, Ross
AU - Robertson, Stuart D.
AU - Hevia, Eva
N1 - The version posted must include a notice on the first page as follows: "This is the peer reviewed version of the following article: Roberts, A. J., Kennedy, A. R., McLellan, R., Robertson, S. D., & Hevia, E. (2016). Synthesis, structure and solution studies on mixed aryl/alkyl lithium zincates. European Journal of Inorganic Chemistry, 4752-4760. DOI: 10.1002/ejic.201601020, which has been published in final form at http://dx.doi.org/10.1002/ejic.201601020. This article may be used for non-commercial purposes in accordance With Wiley-VCH Terms and Conditions for self-archiving".
PY - 2016/9/22
Y1 - 2016/9/22
N2 - Novel homo- and heteroleptic lithium zincates have been prepared by cocomplexation reactions of Zn(CH2SiMe3)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 [Li4Zn3Ph5(CH2SiMe3)5]⋡ (1). Combining Zn(CH2SiMe3)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(CH2SiMe3)2Ph] (2) and homoleptic [(TMEDA)LiZn(CH2SiMe3)3] (3), the result of a disproportionation process, respectively. NMR spectroscopic studies suggest that 2 and 3 retain their discrete contacted ion-pair solid-state structures in benzene solution. Variable-temperature NMR spectroscopic studies of 2 in [D8]THF reveal a complex equilibrium also including [LiZn(CH2SiMe3)3], [LiZn(CH2SiMe3)Ph2] and [LiZnPh3], an equilibrium process analogous to that of 1 in THF. This study further highlights the complexity of these reactions, which at first would appear simple.
AB - Novel homo- and heteroleptic lithium zincates have been prepared by cocomplexation reactions of Zn(CH2SiMe3)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 [Li4Zn3Ph5(CH2SiMe3)5]⋡ (1). Combining Zn(CH2SiMe3)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(CH2SiMe3)2Ph] (2) and homoleptic [(TMEDA)LiZn(CH2SiMe3)3] (3), the result of a disproportionation process, respectively. NMR spectroscopic studies suggest that 2 and 3 retain their discrete contacted ion-pair solid-state structures in benzene solution. Variable-temperature NMR spectroscopic studies of 2 in [D8]THF reveal a complex equilibrium also including [LiZn(CH2SiMe3)3], [LiZn(CH2SiMe3)Ph2] and [LiZnPh3], an equilibrium process analogous to that of 1 in THF. This study further highlights the complexity of these reactions, which at first would appear simple.
KW - zincates
KW - lithium
KW - solvent effects
KW - bimetallic chemistry
KW - cocomplexation
UR - http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-0682c
U2 - 10.1002/ejic.201601020
DO - 10.1002/ejic.201601020
M3 - Article
SN - 1434-1948
SP - 4752
EP - 4760
JO - European Journal of Inorganic Chemistry
JF - European Journal of Inorganic Chemistry
ER -