Solvent-Dependent Substrate Reduction by {Sm[N(SiMe₃)₂]₂(THF)₂}. An Alternative Approach for Accelerating the Rate of Substrate Reduction by Sm(II)

Abstract

The impact of solvent on electron transfer from Sm(II) to substrates was measured by determining the rate of reduction of 1-bromo-, 1-chlorododecane, and 3-pentanone in THF and hexanes using the highly soluble reductant {Sm[N(SiMe3)2]2(THF)2}. Rates were found to be 3 orders of magnitude faster in hexanes than THF, and reductions of alkyl halides were inverse first order in THF. These findings show the solvent milieu significantly impacts the rate of substrate reduction, a consideration that may prove useful in synthesis.

Trivalent Rare-Earth-Metal Bis(trimethylsilyl)amide Halide Complexes by Targeted Oxidations

“…Finally, the present study not only embarks on an alternative strategy for the synthesis of rare-earth-metal compounds of the type “Ln­[N­(SiMe 3 ) 2 ] x (halogenido) y ” ( x + y = 3) but might be also enlightening from the perspective of organic chemistry. In particular, Evans’ complex Sm­[N­(SiMe 3 ) 2 ] 2 (thf) 2 is currently being investigated as a powerful reductant for the solvent-dependent dehalogentation of alkyl halides. − …”

Cationic Titanocene(III) Complexes for Catalysis in Single‐Electron Steps

“…For [Cp 2 Ti] + , THF is superior to the strongly coordinating CH 3 CN, which inhibits epoxide binding. Solvent coordination to titanium can thus affect the overall rate of electron transfer to substrate 9…”

CO reductive oligomerization by a divalent thulium complex and CO2-induced functionalization

“…An inhibitory role of THF in the reduction of organic substrates by Sm( ii ) complexes has previously been observed in the literature. 30 Interestingly, in the U( iii ) systems reported by Arnold and co-workers, THF coordination was found to completely stop the reactivity towards CO. 17 g , h Such a different behavior may originate in the steric demand of the Cp ttt ligands that induces weak and reversible coordination of the usually strongly bound THF donor. 21 a A greater degree of covalency of U–L vs. Ln–L bonds (L = THF or other donor ligands) may also contribute to decrease the L lability and suppress reactivity for U( iii ) systems in donor solvents.…”