Alkali metal influences in aluminyl complexes
Grams S, Mai J, Langer J, Harder S (2022)
Publication Type: Journal article
Publication year: 2022
Journal
DOI: 10.1039/d2dt02111k
Abstract
The previously reported potassium aluminyl complex [(BDI-H)Al−K+]2 was converted in Li+ or Na+ salts by a salt metathesis reaction with Li(BPh4) or Na(BPh4), respectively; BDI-H = dianionic [(DIPP)N-C(Me) 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 C(H)-C( CH2)-N(DIPP)2−] and DIPP = 2,6-diisopropylphenyl. The Rb and Cs aluminyl complexes were obtained by reaction of (BDI)Al with RbC8 or CsC8; BDI = HC[C(Me)N(DIPP)]2. Crystal structures of two monomers, (BDI-H)Al−Li+·(Et2O)2 and (BDI-H)Al−Na+·(Et2O)(TMEDA), and four dimers [(BDI-H)Al−M+]2 (M = Li, Na, Rb, Cs) are discussed. Lewis base-free dimers [(BDI-H)Al−M+]2 crystallize either as slipped dimers (Li+, Na+) in which each Al center features only one Al-M contact or as a symmetric dimer (K+, Rb+, Cs+) in which the cation bridges both Al centers. The dimer with the largest cation (Cs+) shows Cs⋯CH2 C interactions between dimers, resulting in a coordination polymer. AIM and charge analysis reveal highly ionic Al-M bonds with strong polarization of the Al lone-pair towards the smaller cation Li+ and Na+. The Al-M bonds become weaker from Li to Cs. Calculated dimerization energies suggest that in apolar solvents only complexes with the heavier metals Rb and Cs may be in a monomer-dimer equilibrium. This is confirmed by DOSY measurements in benzene. Dimeric aluminyl complexes with heavier alkali metals (K-Cs) react with benzene to give a double C-H activation in para-positions.
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How to cite
APA:
Grams, S., Mai, J., Langer, J., & Harder, S. (2022). Alkali metal influences in aluminyl complexes. Dalton Transactions. https://doi.org/10.1039/d2dt02111k
MLA:
Grams, Samuel, et al. "Alkali metal influences in aluminyl complexes." Dalton Transactions (2022).
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