Rösch B, Martin J, Eyselein J, Langer J, Wiesinger M, Harder S (2021)
Publication Type: Journal article
Publication year: 2021
DOI: 10.1021/acs.organomet.1c00199
The complex (DMAT)2Ba·(THF)2 (DMAT = 2-dimethylamino-α-trimethylsilylbenzyl) was prepared by a salt metathesis reaction between (DMAT)K and BaI2 in THF, and crystals were isolated in 83% yield. This monomeric complex dissolves well in aromatic or ethereal solvents and is also stable at higher temperatures in solution. Structural details and NMR parameters reveal a high degree of charge delocalization in the DMAT aryl ring. Comparison with identical Ca and Sr complexes, (DMAT)2Ae·(THF)2 (Ae = Ca and Sr), shows that the extent of delocalization increases down group 2: Ca < Sr < Ba. Due to chirality at the benzylic carbon, in solution the heterochiral R,S-isomer and homochiral R,R/S,S-isomers exist in equilibrium. A temperature-dependent NMR study gives an estimate of the Ae-C and Ae-N bond energies which decrease down the group: Ca > Sr > Ba. Although the DMAT carbanion is stabilized by resonance and negative hyperconjugation, (DMAT)2Ba·(THF)2 is still a very potent deprotonation reagent. Double deprotonation of Ph3SiNH2 gave the first Ba imido complex. A similar reaction using (DMAT)2Sr·(THF)2 gave the analogue Sr imido complex. Comparison with reported structures shows trends for the full series [(Ph3SiN)Ae·(THF)]4 (Ae = Mg, Ca, Sr, and Ba) which crystallize as tetramers with very stable, ionically bound heterocubane Ae4N4 cores.
APA:
Rösch, B., Martin, J., Eyselein, J., Langer, J., Wiesinger, M., & Harder, S. (2021). Application of a Stable and Soluble Dibenzylbarium Reagent in the Synthesis of a Barium Imido Cluster. Organometallics. https://dx.doi.org/10.1021/acs.organomet.1c00199
MLA:
Rösch, Bastian, et al. "Application of a Stable and Soluble Dibenzylbarium Reagent in the Synthesis of a Barium Imido Cluster." Organometallics (2021).
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