Paper on Energetics of paramagnetic oxide clusters accepted by PCCP

Energetics of paramagnetic oxide clusters: the Fe(III) oxyhydroxy Keggin ion

Phys. Chem. Chem. Phys., 2020, DOI: 10.1039/C9CP05795A. Link

C. A. Ohlin


Abstract:
 The energetics of the different spin states of the five Baker-Figgis isomers of the iron(III) Keggin ion, [Fe(O4)(Fe(OH)2 (OH2))12]7+, has been investigated using density functional theory in order to demonstrate how the energy landscape of medium-to-large discrete paramagnetic transition metal oxide clusters with large numbers of antiferromagnetically coupled centres can be resolved. Antiferromagnetic coupling causes the energies to span a surprisingly large range of 30 kcal/mol, as determined by calculating the energies of all 664 unique spin configurations based on determination of the antiferromagnetic coupling constants by density functional theory. A program which simplifies the resolution of the energetics of this type of systems is also provided.

Paper on fullerene anion chemistry accepted by Chemical Science

Hydrocarbon-soluble, hexaanionic fulleride complexes of magnesium
Chem. Sci., 2019, 10, 10755-10764. Link
Samuel R. Lawrence,  C. André Ohlin, David B. Cordes,  Alexandra M. Z. Slawin, Andreas Stasch

Abstract: The reaction of the magnesium(I) complexes [{( Arnacnac)Mg}2], ( Arnacnac = HC(MeCNAr)2 , Ar =Dip (2,6-iPr2C6H3), Dep (2,6-Et2C6H3), Mes (2,4,6-Me3C6H2), Xyl (2,6-Me2C6H3 )) with fullerene C60 afforded a series of hydrocarbon-soluble fulleride complexes [{(Arnacnac)Mg}nC60], predominantly with n = 6, 4 and 2. 13C{1H} NMR spectroscopic studies show both similarities (n = 6) and differences (n = 4, 2) to previously characterised examples of fulleride complexes and materials with electropositive metal ions. The molecular structures of[{(Arnacnac)Mg}nC60] with n = 6, 4 and 2 can be described as inverse  coordination complexes of n [(Arnacnac)Mg]+ ions with C60n- anions showing predominantly ionic metal-ligand interactions, and include the first well-defined and soluble complexes of the C606- ion. Experimental studies show the flexible ionic nature of the {(Arnacnac)Mg}+····C606-  coordination bonds. DFT calculations on the model complex [{(Menacnac)Mg}6C60] (Menacnac = HC(MeCNMe)2) support the formulation as an ionic complex with a centralC606- anion and comparable frontier orbitals toC606- with a small HOMO-LUMO gap. The reduction of C60 to its hexaanion gives an indication about the reducing strength of dimagnesium(I) complexes.

Paper on smectite hydration accepted by ACS Earth and Space Chemistry

Deconvolution of Smectite Hydration Isotherms

Authors: Jerry Lindholm, Jean-Francois Boily and Michael Holmboe.
Link: doi.org/10.1021/acsearthspacechem.9b00178
Synopsis:
Sorption isotherm models have traditionally served as an invaluable tool to characterize synthesized and natural mineral particles, but often fail to describe the behavior of swelling materials. This research presents a novel composite isotherm model that describes water uptake by adsorption, step-wise intercalation, and condensation.

Paper on microwave synthesis accepted by European Journal of Inorganic Chemistry

Microwave Synthesis of Alkali-Free Hexaniobate, Decaniobate, and Hexatantalate Polyoxometalate Ions
in Eur. J. Inorg. Chem.201935, 3913-3918.   Link
M. A. Rambaran, M. Pascual-Borràs and C. A. Ohlin

Abstract:
 Microwave synthesis of polyoxoniobates and -tantalates circumvents the prolonged heating required by conventional hydrothermal methods, while providing comparable or greater yields. Microwave irradiation allows synthesis of polyoxoniobates from anhydrous niobium pentoxide, in lieu of niobic acid and sets the precedent for the discovery of new polyoxoniobates and -tantalates.