Structural and magnetic diversity in alkali-metal Manganate chemistry : evaluating donor and alkali-metal effects in co-complexation processes

Uzelac, Marina and Borilovic, Ivana and Amores, Marco and Cadenbach, Thomas and Kennedy, Alan R. and Aromí, Guillem and Hevia, Eva (2016) Structural and magnetic diversity in alkali-metal Manganate chemistry : evaluating donor and alkali-metal effects in co-complexation processes. Chemistry - A European Journal, 22 (14). pp. 4843-4854. ISSN 0947-6539 (https://doi.org/10.1002/chem.201504956)

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Abstract

By exploring co-complexation reactions between the manganese alkyl Mn(CH2SiMe3)2 and the heavier alkali-metal alkyls M(CH2SiMe3) (M=Na, K) in a benzene/hexane solvent mixture and in some cases adding Lewis donors (bidentate TMEDA, 1,4-dioxane, and 1,4-diazabicyclo[2,2,2] octane (DABCO)) has produced a new family of alkali-metal tris(alkyl) manganates. The influences that the alkali metal and the donor solvent impose on the structures and magnetic properties of these ates have been assessed by a combination of X-ray, SQUID magnetization measurements, and EPR spectroscopy. These studies uncover a diverse structural chemistry ranging from discrete monomers [(TMEDA)2MMn(CH2SiMe3)3] (M=Na, 3; M=K, 4) to dimers [(KMn(CH2SiMe3)3C6H6)2] (2) and [(NaMn(CH2SiMe3)3)2(dioxane)7] (5); and to more complex supramolecular networks [(NaMn(CH2SiMe3)3)∞] (1) and [(Na2Mn2(CH2SiMe3)6(DABCO)2)∞] (7)). Interestingly, the identity of the alkali metal exerts a significant effect in the reactions of 1 and 2 with 1,4-dioxane, as 1 produces coordination adduct 5, while 2 forms heteroleptic [((dioxane)6K2Mn2(CH2SiMe3)4(O(CH2)2OCH=CH2)2)∞] (6) containing two alkoxide-vinyl anions resulting from α-metalation and ring opening of dioxane. Compounds 6 and 7, containing two spin carriers, exhibit antiferromagnetic coupling of their S=5/2 moments with varying intensity depending on the nature of the exchange pathways.

  • Item type:Article
    ID code:55900
    Dates:
    Date
    Event
    24 February 2016
    Published
    28 December 2015
    Accepted
    Notes:This is the peer reviewed version of the following article: Uzelac, M., Borilovic, I., Amores, M., Cadenbach, T., Kennedy, A. R., Aromí, G. and Hevia, E. (2016), Structural and Magnetic Diversity in Alkali-Metal Manganate Chemistry: Evaluating Donor and Alkali-Metal Effects in Co-complexation Processes. Chem. Eur. J., which has been published in final form at DOI: 10.1002/chem.201504956 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
    Subjects:Science > Chemistry
    Department:Faculty of Science > Pure and Applied Chemistry
    Depositing user: Pure Administrator
    Date deposited:15 Mar 2016 14:34
    Last modified:13 Apr 2024 08:26
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/55900
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