This work is mainly focused on understanding the complex-forming behavior of diethylzinc with neutral phosphine ligands such as triphenylphosphine (PPh3) to yield [Zn(PPh3)2Et2]. The complex formation in solution is observed in the presence of a large excess of diethylzinc, but leaving an insoluble solid on aging. The product formed in solution was analyzed by spectroscopic data. 31P-NMR was also used as a tool to observe this behavior, i.e., the disappearance of the chemical shift of PPh3 (δ -5.45) requires 14-fold excess of ZnEt2 in solution. The alkyl chains reduce the Lewis acidity on Zn and thereby the formation of phosphine adducts is restricted. Results obtained from orbital analyses calculations reveal that the LUMO appears to be asymmetrically distributed, and localized on one of the PPh3 ligands. The length of alkyl chains also influence the stability of [Zn(PPh3)2R2] and the longer chains on Zn impart less stability. © 2016 Taylor & Francis Group, LLC.
|Phosphorus, Sulfur, and Silicon and the Related Elements
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