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Ohlin, C. A. & Casey, W. H. (2018). 17O NMR as a Tool in Discrete Metal Oxide Cluster Chemistry. In: Webb, Graham A. (Ed.), Annual Reports on NMR Spectroscopy: (pp. 187-248). Elsevier
Open this publication in new window or tab >>17O NMR as a Tool in Discrete Metal Oxide Cluster Chemistry
2018 (English)In: Annual Reports on NMR Spectroscopy / [ed] Webb, Graham A., Elsevier, 2018, p. 187-248Chapter in book (Refereed)
Abstract [en]

This chapter covers recent developments in 17O NMR spectroscopy as applied to discrete metal oxide clusters, particularly in the context of their use as models in geochemistry and catalysis. Dynamic 17O NMR methods based on the McConnell–Bloch equations are explored in depth, and recent advances are reviewed. High-pressure NMR methods are also discussed and reviewed, as are recent developments in the use of density functional theory in the computation of 17O NMR shifts in polyoxometalates. The emphasis of the chapter is on the new developments that promise to reinvigorate 17O NMR as a central tool in the study of aqueous chemical kinetics, with the most urgent challenges being understanding the rates of isotopic substitution into bridging oxygens in clusters.

Place, publisher, year, edition, pages
Elsevier, 2018
Series
Annual Reports on NMR Spectroscopy, ISSN 0066-4103 ; 94
Keywords
O-17 NMR, Polyoxometalates, Solution dynamics, Kinetics, Water, Minerals, Metal oxides, Geochemistry, High-pressure NMR
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-151201 (URN)10.1016/bs.arnmr.2018.01.001 (DOI)000435535700006 ()2-s2.0-85042174204 (Scopus ID)978-0-12-815212-6 (ISBN)
Available from: 2018-09-04 Created: 2018-09-04 Last updated: 2018-09-04Bibliographically approved
Colla, C. A., Casey, W. H. & Ohlin, C. A. (2018). Computational prediction of Mg-isotope fractionation between aqueous [Mg(OH2)6]2+ and brucite. Geochimica et Cosmochimica Acta, 227, 64-74
Open this publication in new window or tab >>Computational prediction of Mg-isotope fractionation between aqueous [Mg(OH2)6]2+ and brucite
2018 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 227, p. 64-74Article in journal (Refereed) Published
Abstract [en]

The fractionation factor in the magnesium-isotope fractionation between aqueous solutions of magnesium and brucite changes sign with increasing temperature, as uncovered by recent experiments. To understand this behavior, the Reduced Partition Function Ratios and isotopic fractionation factors (Δ26/24Mgbrucite-Mg(aq)) are calculated using molecular models of aqueous [Mg(OH2)6]2+ and the mineral brucite at increasing levels of density functional theory. The calculations were carried out on the [Mg(OH2)6]2+·12H2O cluster, along with different Pauling-bond-strength-conserving models of the mineral lattice of brucite. Three conclusions were reached: (i) all levels of theory overestimate 〈Mg‒O〉 bond distances in the aqua ion complex relative to Tutton’s salts; (ii) the calculations predict that brucite at 298.15 K is always enriched in the heavy isotope, in contrast with experimental observations; (iii) the temperature dependencies of Wimpenny et al. (2014) and Li et al. (2014) could only be achieved by fixing the 〈Mg‒O〉 bond distances in the [Mg(OH2)6]2+·12H2O cluster to values close to those observed in crystals that trap the hydrated ion.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Mg-isotopes, Isotope fractionation, Brucite, Density functional theory, Electronic structure
National Category
Geochemistry
Identifiers
urn:nbn:se:umu:diva-146417 (URN)10.1016/j.gca.2018.02.005 (DOI)000427612700005 ()
Available from: 2018-05-08 Created: 2018-05-08 Last updated: 2018-06-09Bibliographically approved
Ohlin, C. A. & Pascual-Borràs, M. (2018). Protonation and water exchange kinetics in sandwich polyoxometalates. Dalton Transactions, 47(38), 13602-13607
Open this publication in new window or tab >>Protonation and water exchange kinetics in sandwich polyoxometalates
2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 38, p. 13602-13607Article in journal (Refereed) Published
Abstract [en]

Density functional theory is used to explore the locus and consequences of protonation in [Zn4(HO)2(PW9O34)2]10−. The results are used to explain recent observations regarding the contrasting pH effects on the water-ligand exchange in [Mn4(H2O)2(P2W15O56)2]16− and [Co4(H2O)2(P2W15O56)2]16−, and the general effect of protonation on solvent exchange in metal oxides is discussed.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
Keywords
Inorganic chemistry, polyoxometalates, protonation, tungstate, density functional theory, computational chemistry
National Category
Inorganic Chemistry Theoretical Chemistry
Research subject
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-151689 (URN)10.1039/C8DT02342E (DOI)000446199500037 ()30207367 (PubMedID)
Funder
The Kempe Foundations, JCK-1719
Available from: 2018-09-10 Created: 2018-09-10 Last updated: 2018-12-13Bibliographically approved
Knighton, R. C., Emerson-King, J., Rourke, J. P., Ohlin, C. A. & Chaplin, A. B. (2018). Solution, Solid-State, and Computational Analysis of Agostic Interactions in a Coherent Set of Low-Coordinate Rhodium(III) and Iridium(III) Complexes. Chemistry - A European Journal, 24(19), 4927-4938
Open this publication in new window or tab >>Solution, Solid-State, and Computational Analysis of Agostic Interactions in a Coherent Set of Low-Coordinate Rhodium(III) and Iridium(III) Complexes
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2018 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 19, p. 4927-4938Article in journal (Refereed) Published
Abstract [en]

A homologous family of low‐coordinate complexes of the formulation trans‐[M(2,2′‐biphenyl)(PR3)2][BArF4] (M=Rh, Ir; R=Ph, Cy, iPr, iBu) has been prepared and extensively structurally characterised. Enabled through a comprehensive set of solution phase (VT 1H and 31P NMR spectroscopy) and solid‐state (single crystal X‐ray diffraction) data, and analysis in silico (DFT‐based NBO and QTAIM analysis), the structural features of the constituent agostic interactions have been systematically interrogated. The combined data substantiates the adoption of stronger agostic interactions for the IrIII compared to RhIII complexes and, with respect to the phosphine ligands, in the order PiBu3>PCy3>PiPr3>PPh3. In addition to these structure–property relationships, the effect of crystal packing on the agostic interactions was investigated in the tricyclohexylphosphine complexes. Compression of the associated cations, through inclusion of a more bulky solvent molecule (1,2‐difluorobenzene vs. CH2Cl2) in the lattice or collection of data at very low temperature (25 vs. 150 K), lead to small but statistically significant shortening of the M−H−C distances.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
agostic interactions, crystal engineering, ligand effects, organometallic chemistry, X-ray diffraction
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-147309 (URN)10.1002/chem.201705990 (DOI)000429414100028 ()29377308 (PubMedID)
Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-06-09Bibliographically approved
Pilgrim, C. D., Callahan, J. R., Colla, C. A., Ohlin, A., Mason, H. E. & Casey, W. H. (2017). 27Al MQMAS of the δ-Al13-Keggin†. Dalton Transactions, 46(7), 2249-2254
Open this publication in new window or tab >>27Al MQMAS of the δ-Al13-Keggin†
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2017 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 7, p. 2249-2254Article in journal (Refereed) Published
Abstract [en]

One-dimensional 27Al, 23Na Magic-Angle-Spinning (MAS) NMR and 27Al Multiple-Quantum Magic-Angle-Spinning NMR (MQMAS) measurements are reported for the [small delta]-isomer of the Al13 Keggin structure at high spinning speed and 14.1 T field. Values for the CQ and [small eta] parameters are on the same scale as those seen in other isomers of the Al13 structure. Density functional theory (DFT) calculations are performed for comparison to the experimental fits using the B3PW91/6-31+G* and PBE0/6-31+G* levels of theory, with the Polarizable Continuum Model (PCM).

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-131457 (URN)10.1039/C6DT04263E (DOI)000395864200023 ()
Available from: 2017-02-15 Created: 2017-02-15 Last updated: 2018-06-09Bibliographically approved
Acharya, S. S., Easton, C. D., McCoy, T. M., Spiccia, L., Ohlin, C. A. & Winther-Jensen, B. (2017). Diverse composites of metal-complexes and PEDOT facilitated by metal-free vapour phase polymerization. Reactive & functional polymers, 116, 101-106
Open this publication in new window or tab >>Diverse composites of metal-complexes and PEDOT facilitated by metal-free vapour phase polymerization
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2017 (English)In: Reactive & functional polymers, ISSN 1381-5148, E-ISSN 1873-166X, Vol. 116, p. 101-106Article in journal (Refereed) Published
Abstract [en]

Abstract Oxidative polymerization for the manufacture of conducting polymers such as poly(3,4-ethylenedioxy-thiophene) has traditionally employed iron(III) salts. Demonstrated in this study is vapour phase polymerization of 3,4-ethylenedio- xythiophene using a metal-free oxidant, ammonium persulfate, leading to films with an estimated conductivity of 75 S/cm. Additionally, a route for embedding active transition metal complexes into these poly(3,4-ethylenedioxythiophene)/-poly(styrene-4-sulfonate) (PEDOT/PSS) films via vapour assisted complexation is outlined. Here, the vapour pressure of solid ligands around their melting temperatures was exploited to ensure complexation to metal ions added into the oxidant mixture prior to polymerization of PEDOT. Four composite systems are discussed, viz. PEDOT/PSS embedded with tris(8-hydroxyquinolinato)cobalt(III), tris(2,2-bipyridine)cobalt(II), tris(1,10- phenanthroline)cobalt(II) and tris(8-hyd-roxyquinolinato)aluminium(III). Using these composites, electrochemical reduction of nitrite to ammonia with a faradaic efficiency of 61% was reported.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Conducting polymers, Vapour pressure, Reduction, Nitrite, Ammonia
National Category
Materials Chemistry Inorganic Chemistry Polymer Chemistry
Identifiers
urn:nbn:se:umu:diva-135508 (URN)10.1016/j.reactfunctpolym.2017.04.008 (DOI)000403519800013 ()
Available from: 2017-05-30 Created: 2017-05-30 Last updated: 2018-06-09Bibliographically approved
Hawley, A. L., Ohlin, C. A., Fohlmeister, L. & Stasch, A. (2017). Heavier Group 13 Metal(I) Heterocycles Stabilized by Sterically Demanding Diiminophosphinates: a Structurally Characterized Monomer–Dimer Pair For Gallium. Chemistry - A European Journal, 23(2), 447-455
Open this publication in new window or tab >>Heavier Group 13 Metal(I) Heterocycles Stabilized by Sterically Demanding Diiminophosphinates: a Structurally Characterized Monomer–Dimer Pair For Gallium
2017 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 2, p. 447-455Article in journal (Refereed) Published
Abstract [en]

We have synthesized and characterized the monomeric diiminophosphinate-stabilized Group 13 metal(I) complexes [DipLE:], DipL=Ph2P(NDip)2, Dip=2,6-iPr2C6H3; E=Ga (1), In (2) and Tl (3). In addition, we structurally characterized the dimeric complex [(DipLGa)2], 12. Similar synthetic attempts using MesL=Ph2P(NMes)2, Mes=2,4,6-Me3C6H2 afforded product mixtures from which the mixed oxidation state species [(MesL)3Ga4I3] 4 was isolated. [DipLGa:] 1 is converted with dry air to the gallium(III) oxide species [(DipLGaO)2] 5. Density Functional Theory studies on [DipLE:] and [(DipLE)2], E=Al−Tl, shed light on the bonding in these compounds and show that the newly formed E−E bonding interactions can be described as weak single σ-bond with no significant π-bonding contribution for E=Al, Ga. A large contribution to the dimer binding enthalpies results from London dispersion forces.

Keywords
Group 13 elements, low valent main group compounds, metal–metal interactions, N-ligands, O–O activation
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-130166 (URN)10.1002/chem.201604495 (DOI)000393618700032 ()27813169 (PubMedID)
Available from: 2017-01-13 Created: 2017-01-13 Last updated: 2018-06-09Bibliographically approved
Spillane, S., Sharma, R., Zavras, A., Mulder, R., Ohlin, C. A., Goerigk, L., . . . Ritchie, C. (2017). Non-aqueous microwave-assisted syntheses of deca- and hexa-molybdovanadates. Angewandte Chemie International Edition, 56, 8568-8572
Open this publication in new window or tab >>Non-aqueous microwave-assisted syntheses of deca- and hexa-molybdovanadates
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2017 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 56, p. 8568-8572Article in journal (Refereed) Published
Abstract [en]

We report a new approach for the synthesis of heterohexa- and heterodecametalates via the use of non-aqueous, microwave-assisted reaction conditions. The two novel molybdovanadates have been isolated and characterized in the solid and solution states using single-crystal X-ray diffraction, FT-IR, UV/Vis, multinuclear NMR spectroscopy, and ESI-MS. The relative stabilities of the possible structural isomers were probed using dispersion-corrected DFT calculations for both polyoxometalate systems.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2017
Keywords
microwave chemistry, polyoxometalates, solution dynamics, spectroscopy, structural reorganization
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-132118 (URN)10.1002/anie.201608589 (DOI)000404739200048 ()28090725 (PubMedID)
Note

Special Issue: SI

Available from: 2017-03-05 Created: 2017-03-05 Last updated: 2018-06-09Bibliographically approved
Sindlinger, C. P., Lawrence, S. R., Acharya, S., Ohlin, C. A. & Stasch, A. (2017). PNacPNacE: (E = Ga, In, Tl) - monomeric group 13 metal(I) heterocycles stabilized by a sterically demanding bis(iminophosphoranyl)methanide. Dalton Transactions, 46(48), 16872-16877
Open this publication in new window or tab >>PNacPNacE: (E = Ga, In, Tl) - monomeric group 13 metal(I) heterocycles stabilized by a sterically demanding bis(iminophosphoranyl)methanide
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2017 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 48, p. 16872-16877Article in journal (Refereed) Published
Abstract [en]

The salt metathesis reaction of the sterically demanding bis(iminophosphoranyl)methanide alkali metal complexes LM (L-=HC(Ph(2)PvNDip)(2)(-), Dip=2,6-(Pr2C6H3)-Pr-i; M =Li, Na, K) with "GaI", InBr or TlBr afforded the monomeric group 13 metal(I) complexes LE:, E = Ga (1), In (2) and Tl (3) in moderate yields, and small quantities of LGaI2 4 in the case of Ga, respectively. The molecular structures of LE: 1-3 from X-ray single crystal diffraction show them to contain puckered six-membered rings with N, N'-chelating methanide ligands and two-coordinated metal(I) centres. Reduction reactions of LAlI2 5, prepared by iodination of LAlMe2, were not successful and no aluminium(I) congener could be prepared so far. DFT studies on LE:, E =Al-Tl, were carried out and support the formulation as an anionic, N, N'-chelating methanide ligand coordinating to group 13 metal(I) cations. The HOMOs of the molecules for E = Al-In show a dominant contribution from a metal-based lone pair that is high in s-character.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-143502 (URN)10.1039/c7dt04048b (DOI)000417846200018 ()29188251 (PubMedID)
Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2018-06-09Bibliographically approved
Acharya, S., Winther-Jensen, B., Spiccia, L. & Ohlin, A. C. (2017). Rates of water exchange in 2,2'-bipyridine and 1,10-phenanthroline complexes of CoII and MnII. Australian journal of chemistry (Print), 70(6), 751-754
Open this publication in new window or tab >>Rates of water exchange in 2,2'-bipyridine and 1,10-phenanthroline complexes of CoII and MnII
2017 (English)In: Australian journal of chemistry (Print), ISSN 0004-9425, E-ISSN 1445-0038, Vol. 70, no 6, p. 751-754Article in journal (Refereed) Published
Abstract [en]

The rates and activation parameters of water exchange at pH 3.0 have been determined using variable temperature 17O NMR spectroscopy for four CoII complexes and one MnII complex: [Co(bpy)(H2O)4]2+, [Co(bpy)2 (H2O)2]2+, [Co(phen)-(H2O)4]2+, [Co(phen)2 (H2O)2]2+, and [Mn(bpy)(H2O)4]2+ (bpy = 2,2′-bipyridyl and phen = 1,10-phenanthroline). Substitution of aquo ligands with 1,10-phenanthroline or 2,2′-bipyridyl leads to an increase in the rate of exchange in the manganese complexes, from k298 (1.8 ± 0.1) × 107 s-1 for [Mn(H2O)6]2+ to (7.2 ± 0.3) × 107 s-1 for [Mn(phen)2 (H2O)2]2+, whereas the trends are more complex for the cobalt complexes. We have used the new data in conjunction with literature data for similar complexes to analyse the effect of M–OH2 distance and degree of substitution.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-132119 (URN)10.1071/CH16667 (DOI)000402033800016 ()
Available from: 2017-03-05 Created: 2017-03-05 Last updated: 2018-06-09Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-3804-6421

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