Structure of Jahn–Teller distorted solvated copper(ii) ions in solution, and in solids with apparently regular octahedral coordination geometry

Persson, Ingmar; Persson, Per; Sandström, Magnus; Ullström, Ann-Sofi

doi:10.1039/b200698g

Cited by 176 publications

(206 citation statements)

References 62 publications

(91 reference statements)

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“…According to EXAFS spectroscopy, copper was bound to four oxygens at about 1.95 Å in the first shell (SM , Table S7), consistent with a Jahn-Teller-distorted octahedron (Persson et al, 2002). A contribution from nitrogen functional groups could not be ruled out as backscattering from oxygen cannot be differentiated from nitrogen by EXAFS.…”

Section: Immobilization Mechanismsmentioning

confidence: 94%

Immobilization of Cu and As in two contaminated soils with zero-valent iron – Long-term performance and mechanisms

Tiberg

Kumpienė

Gustafsson

et al. 2016

Applied Geochemistry

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Immobilization of trace elements in contaminated soils by zero-valent iron (ZVI) is a promising remediation method, but questions about its long-term performance remain unanswered. To quantify immobilization and predict possible contaminant remobilization on long timescales detailed knowledge about immobilization mechanisms is needed. This study aimed at assessing the long-term effect of ZVI amendments on dissolved copper and arsenic in contaminated soils, at exploring the immobilization mechanism(s), and at setting up a geochemical model able to estimate dissolved copper and arsenic under different scenarios.Samples from untreated and ZVI-treated plots in two field experiments where ZVI had been added 6 and 15 years ago were investigated by a combination of batch experiments, geochemical modeling and extended X-ray absorption fine structure (EXAFS) spectroscopy.Dissolved copper and arsenic concentrations were described by a multisurface geochemical model with surface complexation reactions, verified by EXAFS. The ZVI remained "reactive" after 6-15 years, i.e. the dissolved concentrations of copper and arsenic were lower in the ZVI-treated than in the untreated soils. There was a shift in copper speciation from organic matter complexes in the untreated soil to surface complexes with iron (hydr)oxides in the ZVI-treated soil. The pH value was important for copper immobilization and ZVI did not have a stabilizing effect if pH was lower than about 6. Immobilization of arsenic was slightly pH-dependent and sensitive to the competition with phosphate. If phosphate was ignored in the modeling, the dissolution of arsenate was greatly underestimated.

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Section: Immobilization Mechanismsmentioning

confidence: 94%

Immobilization of Cu and As in two contaminated soils with zero-valent iron – Long-term performance and mechanisms

Tiberg

Kumpienė

Gustafsson

et al. 2016

Applied Geochemistry

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“…[1][2][3][4][5] Detailed information on ligands arrangement around the Cu(II) ion is only available in the solid state [6][7][8][9][10][11][12][13] whereas the structural information in the aqueous phase [13][14][15][16][17][18][19][20] is less definitive and available only for few Cu 2+ complexes. Although static [20][21][22][23][24][25][26][27][28][29][30] and dynamic [31][32][33][34][35][36][37] electronic structure calculations can, in principle, provide such information, realistic modeling of Cu(II) complexes in aqueous solution with highly flexible coordination environment still remains a challenge.…”

Section: Introductionmentioning

confidence: 99%

“…Another direct consequence of the Jahn-Teller effect is the flexibility (plasticity) of the coordination geometry of Cu(II) which can adopt a variety of coordination geometries in the crystalline phase. [6][7][8][9][10][11][12][13] For example, crystal structures of Cu(II)-amino acids complexes with four-, five-, and six-coordinate geometries are all common, suggesting that energetic differences between them are small. Consistent with the Jahn-Teller effect, many of these structures include irregular or distorted coordination geometries.…”

Section: Introductionmentioning

confidence: 99%

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Hydration of Copper(II): New Insights from Density Functional Theory and the COSMO Solvation Model

et al. 2008

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The hydrated structure of the Cu(II) ion has been a subject of ongoing debate in the literature. In this article, we use density functional theory (B3LYP) and the COSMO continuum solvent model to characterize the structure and stability of [Cu(H 2 2+ clusters as a function of coordination number (4, 5, and 6) and cluster size (n ) 4-18). We find that the most thermodynamically favored Cu(II) complexes in the gas phase have a very open four-coordinate structure. They are formed from a stable square-planar [Cu(H 2 O) 8 ] 2+ core stabilized by an unpaired electron in the Cu(II) ion d x 2 -y 2 orbital. This is consistent with cluster geometries suggested by recent mass-spectrometric experiments. In the aqueous phase, we find that the more compact five-coordinate square-pyramidal geometry is more stable than either the four-coordinate or six-coordinate clusters in agreement with recent combined EXAFS and XANES studies of aqueous solutions of Cu(II). However, a small energetic difference (∼1.4 kcal/mol) between the five-and six-coordinate models with two full hydration shells around the metal ion suggests that both forms may coexist in solution.

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“…The apparent absence of Jahn-Teller bond length distortions in other copper(II) complexes has been reported (ref. 28 and references therein). Thus, based on the results of x-ray (29-33) or neutron (34) diffraction studies, other copper(II) systems with 3-fold symmetry axes have appeared to have apparently equivalent (or partially averaged) (24) coordination bond lengths.…”

Section: X-ray and Computationalmentioning

confidence: 99%

Manganese(II), iron(II), cobalt(II), and copper(II) complexes of an extended inherently chiral tris-bipyridyl cage

Perkins

Lindoy

McAuley

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Manganese(II), iron(II),encapsulation ͉ template ͉ transition metal ͉ triple helix S ince the first reports of the binding of metal ions in the cavities of aza molecular cages (1, 2), the metal complexation chemistry of such systems has received continuing attention (3-9). Such 3D cages will normally result in enhanced steric and electronic restraints on the bound metal ion relative to related 2D macrocyclic systems (the ''cryptate effect'') (10, 11), with unusual spectral, photoactive, and electrochemical properties also often resulting.We have previously reported the synthesis of new cages that include 1 (12, 13) (Scheme 1) and 2 (14, 15) (Scheme 2) by means of stepwise procedures based on functional group interconversions from corresponding dialdehyde precursors. A CoreyPauling-Koltun model of 2 in its exo-exo configuration indicated that it has a ''slot-like'' cavity. Recrystallization of this cage from benzene yielded the corresponding host-guest product in which a benzene molecule is symmetrically incorporated in the cage's cavity, aligned normal to the long axis (14). An additional feature of these cage structures is that the position of each set of three benzo rings results in there being a strong tendency for the corresponding bridgehead caps to adopt a chiral ''three-bladed propeller'' arrangement about each long axis.In previous studies 2,2-bipyridyl groups have been successfully incorporated in the structures of new cage species; the complexation behavior of such species toward a variety of metal ions and other guest species has been investigated (16-21). In a recent communication we (22) reported the successful expansion of the size of the cavity in 2 by replacement of each of the 2,6-pyridyl groups with 5,5Ј-substituted 2,2Ј-bipyridyl moieties to yield the extended cage 3 [R ϭ tertiary butyl (t-Bu)] (Scheme 3). Semiempirical (pm3) calculations indicated that 3 (R ϭ H) in its exo-exo configuration should readily accept a divalent octahedral metal ion such that the latter induces a triple helical twist about the (long) cage axis; comparison of Corey-Pauling-Koltun models indicated that 3 (R ϭ t-Bu) will almost certainly exhibit similar behavior. In both cases metal-ion-induced helicity is expected to be aided by the presence of the six salicycl-derived fragments adjacent to the nitrogen bridgeheads (see below). Indeed the x-ray structure of the nickel(II) complex of 3 (R ϭ t-Bu) confirmed that the presence of this central metal results in a triple-helical twist of the cage and that the twist extends Ϸ22 Å along its axial length. The cage is present in its exo-exo configuration, with the nickel bound to the six pyridyl nitrogens to yield an octahedral coordination geometry. The x-ray structure of metal-free 3 (R ϭ t-Bu) was also obtained (22). In this case the cage adopts a ''loose'' helical arrangement in the solid state. Nevertheless, a solution NMR study in CDCl 3 and semiempirical [pm3] calculations both indicate that it is conformationally flexible. The above results are in accord with the origin...

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Structure of Jahn–Teller distorted solvated copper(ii) ions in solution, and in solids with apparently regular octahedral coordination geometry

Cited by 176 publications

References 62 publications

Immobilization of Cu and As in two contaminated soils with zero-valent iron – Long-term performance and mechanisms

Immobilization of Cu and As in two contaminated soils with zero-valent iron – Long-term performance and mechanisms

Hydration of Copper(II): New Insights from Density Functional Theory and the COSMO Solvation Model

Manganese(II), iron(II), cobalt(II), and copper(II) complexes of an extended inherently chiral tris-bipyridyl cage

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