TY - JOUR
T1 - Structural and magnetic diversity in alkali-metal Manganate chemistry
T2 - evaluating donor and alkali-metal effects in co-complexation processes
AU - Uzelac, Marina
AU - Borilovic, Ivana
AU - Amores, Marco
AU - Cadenbach, Thomas
AU - Kennedy, Alan R.
AU - Aromí, Guillem
AU - Hevia, Eva
N1 - 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.
PY - 2016/2/24
Y1 - 2016/2/24
N2 - 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.
AB - 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.
KW - alkali metals
KW - cooperativity
KW - lewis bases
KW - magnetism
KW - Manganese
UR - http://www.scopus.com/inward/record.url?scp=84959386277&partnerID=8YFLogxK
U2 - 10.1002/chem.201504956
DO - 10.1002/chem.201504956
M3 - Article
AN - SCOPUS:84959386277
SN - 0947-6539
VL - 22
SP - 4843
EP - 4854
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 14
ER -