Carbon–chalcogen bond formation initiated by [Al(NONDipp)(E)]– anions containing Al–E{16} (E{16} = S, Se) multiple bonds

Matthew Evans, Mathew Anker, Claire McMullin, Sam Neale, Nasir Rajabi, Martyn Coles

Research output: Contribution to journalArticlepeer-review

10 Citations (SciVal)

Abstract

Multiply-bonded main group metal compounds are of interest as a new class of reactive species able to activate and functionalize a wide range of substrates. The aluminium sulfido compound K[Al(NON Dipp)(S)] (NON Dipp = [O(SiMe 2NDipp) 2] 2−, Dipp = 2,6- iPr 2C 6H 3), completing the series of [Al(NON Dipp)(E)] anions containing Al-E{16} multiple bonds (E{16} = O, S, Se, Te), was accessed via desulfurisation of K[Al(NON Dipp)(S 4)] using triphenylphosphane. The crystal structure showed a tetrameric aggregate joined by multiple K⋯S and K⋯π(arene) interactions that were disrupted by the addition of 2.2.2-cryptand to form the separated ion pair, [K(2.2.2-crypt)][Al(NON Dipp)(S)]. Analysis of the anion using density functional theory (DFT) confirmed multiple-bond character in the Al-S group. The reaction of the sulfido and selenido anions K[Al(NON Dipp)(E)] (E = S, Se) with CO 2 afforded K[Al(NON Dipp)(κ 2E,O-EC{O}O)] containing the thio- and seleno-carbonate groups respectively, consistent with a [2 + 2]-cycloaddition reaction and C-E bond formation. An analogous cycloaddition reaction took place with benzophenone affording compounds containing the diphenylsulfido- and diphenylselenido-methanolate ligands, [κ 2E,O-EC{O}Ph 2] 2−. In contrast, when K[Al(NON Dipp)(E)] (E = S, Se) was reacted with benzaldehyde, two equivalents of substrate were incorporated into the product accompanied by formation of a second C-E bond and complete cleavage of the Al-E{16} bonds. The products contained the hitherto unknown κ 2O,O-thio- and κ 2O,O-seleno-bis(phenylmethanolate) ligands, which were exclusively isolated as the cis-stereoisomers. The mechanisms of these cycloaddition reactions were investigated using DFT methods.

Original languageEnglish
Pages (from-to)4635-4646
JournalChemical Science
Volume13
Issue number16
Early online date31 Mar 2022
DOIs
Publication statusPublished - 31 Mar 2022

Bibliographical note

Funding Information:
M. J. E. acknowledges the award of a Victoria University of Wellington Doctoral Scholarship. This research made use of the Balena High Performance Computing (H. P. C.) Service at the University of Bath. Financial support from the EPSRC (EP/R020752/1 – C. L. M., S. E. N. and N. A. R.) and a University Research Fund (URF) grant from Victoria University of Wellington (M. D. A.).

ASJC Scopus subject areas

  • General Chemistry

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