Three oxidative addition routes of alkali metal aluminyls to dihydroaluminates and reactivity with CO2

Banerjee, Sumanta and Ballmann, Gerd M. and Evans, Matthew J. and O'Reilly, Andrea and Kennedy, Alan R. and Fulton, J. Robin and Coles, Martyn P. and Mulvey, Robert E. (2023) Three oxidative addition routes of alkali metal aluminyls to dihydroaluminates and reactivity with CO2. Chemistry - A European Journal, 29 (56). e202301849. ISSN 1521-3765 (https://doi.org/10.1002/chem.202301849)

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Abstract

Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NONDipp)(H)2] (AM = Li, Na, K, Rb, Cs; [NONDipp]2– = [O(SiMe2NDipp)2]2–; Dipp = 2,6-iPr2C6H3) starting from the alkali metal aluminyls, AM[Al(NONDipp)]. Direct H2 hydrogenation of the heavier analogues (AM = Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4-cyclohexadiene (1,4-CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM = Li – Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NONDipp)(H)(SiH2Ph)]. Probing the reaction of Cs[Al(NONDipp)] with 1,4-CHD provided access to a novel inverse sandwich complex, [{Cs(Et2O)}2{Al(NONDipp)(H)}2(C6H6)], containing the 1,4-dialuminated [C6H6]2– dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4-CHD to benzene has been trapped. The synthetic utility of the newly installed Al–H bonds has been demonstrated by their ability to reduce CO2 under mild conditions to form the bis-formate AM[Al(NONDipp)(O2CH)2] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures.

ORCID iDs

Banerjee, Sumanta, Ballmann, Gerd M., Evans, Matthew J., O'Reilly, Andrea, Kennedy, Alan R. ORCID logoORCID: https://orcid.org/0000-0003-3652-6015, Fulton, J. Robin, Coles, Martyn P. and Mulvey, Robert E. ORCID logoORCID: https://orcid.org/0000-0002-1015-2564;
  • Item type:Article
    ID code:86161
    Dates:
    Date
    Event
    9 October 2023
    Published
    10 July 2023
    Published Online
    10 July 2023
    Accepted
    Subjects:Science > Chemistry
    Department:Faculty of Science > Pure and Applied Chemistry
    Depositing user: Pure Administrator
    Date deposited:18 Jul 2023 13:48
    Last modified:16 Nov 2024 01:25
    URI:https://strathprints.strath.ac.uk/id/eprint/86161
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