Structure and Energetics of the Samarium Diiodide−HMPA Complex in Tetrahydrofuran
- 15 June 1999
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 64 (14) , 5251-5255
- https://doi.org/10.1021/jo990484l
Abstract
The role of HMPA as a ligand for SmI2 and the stoichiometry and energetics of formation for the SmI2−HMPA complex in THF were investigated employing UV−vis spectroscopy, isothermal titration calorimetry (ITC), and vapor pressure osmometry (VPO). The aggregation number for SmI2 in THF was found to be 0.98 ± 0.09 over the entire concentration range studied (6.71−84.0 mM), indicating that SmI2 is monomeric. The UV−vis data suggest that four HMPA ligands coordinate to SmI2, and this was supported by ITC experiments. The combined results are consistent with [SmI2(HMPA)4] being the reductant responsible for the unique reactivity exhibited by SmI2−HMPA cosolvent combinations.Keywords
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