Minimal Distortion Pathways in Polyhedral Rearrangements

Casanova, David; Cirera, Jordi; Llunell, Miquel; Alemany, Pere; Avnir, David; Álvarez, Santiago

doi:10.1021/ja036479n

Cited by 390 publications

(366 citation statements)

References 15 publications

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“…Also, the axial solvent molecule contributes to this effect in terms of different energy barrier heights [29]. In order to compare the coordination geometries of the Dy ions, these were analysed using the Shape program [30][31][32]. The results are shown in Table 2, and indicate that the coordination geometries of the Dy ions in 1, 2, 4 and Dy 1 in 3 are close to triangular dodecahedral (TDD) with D 2d symmetry.…”

Section: Structure-property Relationshipmentioning

confidence: 99%

Tuning of Hula-Hoop Coordination Geometry in a Dy Dimer

et al. 2016

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Abstract:The reaction of DyCl 3 with hydrazone Schiff base ligands and sodium acetate in the presence of triethylamine (Et 3 N) as base affords two dysprosium dimers: [Dy 2 (HL1) 2 (OAc) 2 (EtOH)(MeOH)] (1) and [Dy 2 (L2) 2 (OAc) 2 (H 2 O) 2 ]¨2MeOH (2). The Dy III ions in complexes 1 and 2 are linked by alkoxo bridges, and display "hula hoop" coordination geometries. Consequently, these two compounds show distinct magnetic properties. Complex 1 behaves as a field-induced single molecule magnet (SMM), while typical SMM behavior was observed for complex 2. In addition, comparison of the structural parameters among similar Dy 2 SMMs with hula hoop-like geometry reveals the significant role played by coordination geometry and magnetic interaction in modulating the relaxation dynamics of SMMs.

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Section: Structure-property Relationshipmentioning

confidence: 99%

Tuning of Hula-Hoop Coordination Geometry in a Dy Dimer

et al. 2016

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“…This technique is often useful for analyzing a particular structure by calculating its shape measures relative to two different reference polyhedra, conveniently plotted in a "shape map" [33,34]. This visualizes whether that structure lies along the minimal distortion path for the interconversion of the two polyhedra.…”

Section: Introduction To Shape Measuresmentioning

confidence: 99%

“…For six-coordinate metal ions, the minimal distortion pathway between the octahedron and the trigonal prism is usually considered [34], which corresponds to the Bailar trigonal twist [35]. A quantitative evaluation of how close (or how far) the structure is from the minimal distortion path is provided by the path deviation function, quoted as a percentage of the deviation relative to the total length of the path [33,36].…”

Section: Introduction To Shape Measuresmentioning

confidence: 99%

Spin state behavior of iron(II)/dipyrazolylpyridine complexes. New insights from crystallographic and solution measurements

Cook

Mohammed

Sherborne

et al. 2015

Coordination Chemistry Reviews

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“…Not only are the shape measures correlated to the Co···H distance along the reaction path, but it is also seen that all the points in our linear transit pathway have shape measures for the {Co(CO) 4 } fragment that correspond to the minimaldistortion interconversion path between the tetrahedron and the vTBP according to the very small values of the pathdeviation function. [10] For that reason, we can describe the proton-transfer reaction by means of the generalized reaction coordinate [4] that corresponds to the conversion of a {Co(CO) 4 } tetrahedron into a vTBP (Figure 3). Using such a coordinate, the independent reactants are represented by 0 % of the polyhedral path, as the isolated [Co(CO) 4 ] À ion is perfectly tetrahedral.…”

Section: Polyhedral Interconversion Coupled With Protonmentioning

confidence: 99%

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)₄]⁻ Ion

2006

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Proton transfer between ammonium cations and [CoL(CO) 3 ]À ions (L = CO, PR 3 ) has been illustrated by Brammer et al.[1] through a series of crystal structures according to the structure-correlation principle, which states that "if a correlation can be found between two or more independent parameters describing the structure of a given fragment in a variety of environments, then the correlation function maps a minimum energy path in the corresponding parameter space".[2] The two ends of the proton transfer reaction correspond to an ionic pair formed by an ammonium cation and the [CoL(CO) 3 ]À ion (1 a) and independent amine and hydrido carbonyl complexes 1 b. The structures analyzed by Brammer et al. correspond to compounds with NÀH···Co hydrogen bonds, a behavior consistent with the acidity of the hydrido carbonyl complex in water. [3] According to the structure-correlation principle, the variety of H···Co distances found (between 2.63 for a NÀH···Co hydrogen-bonded species and 1.43 for the hydrido complex) should correspond to snapshots along the proton-transfer reaction coordinate. Since the coordination spheres of both the N and Co atoms are significantly affected by the progress of the protontransfer reaction, these systems provide an excellent opportunity to test the applicability of the polyhedral-shape measures as reaction coordinates and to correlate the potential-energy surface with the structural evolution. Therefore, the aim of this communication is to show how DFT calculations provide an energy profile for such a reaction that accounts for the fine details of the distribution of structures along the path and how the proton transfer is coupled to changes in the coordination polyhedra of the N and Co atoms. An outcome of this study is that the energy and the stereochemical changes that accompany the proton transfer can be described as a function of a single parameter, the generalized polyhedral-interconversion coordinate [4] for the transformation of a [CoL(CO) 3 ] À (L = ligand) tetrahedron into a vacant trigonal bipyramid.To represent the general case of an ammonium cation, we took the NH 4 + ion as the simplest example, whereas the family of the [CoL(CO) 3 ]À ions was represented in our calculations by the [Co(CO) 4 ] À ion. To explore the potentialenergy surface, we calculated a linear-transit reaction coordinate for the NH 4 ·[CoL(CO) 3 ] aggregate keeping the Co···H distance fixed and optimizing the rest of the geometry.[5] The two minima and one maximum obtained were fully optimized and could be characterized as stationary points on the potential-energy surface through frequency analysis (geometries and frequencies for the three stationary points are provided in the Supporting Information). The two minima correspond to the two alternative hydrogen-bonding situations: a) N À H···Co, referred to herein as the ion pair, to avoid confusion with the second minimum, and b) N···HÀCo, which we term the hydrogen-bonded complex. The maximum corresponds to a transition state with a delocalized hydrogen bo...

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Minimal Distortion Pathways in Polyhedral Rearrangements

Cited by 390 publications

References 15 publications

Tuning of Hula-Hoop Coordination Geometry in a Dy Dimer

Tuning of Hula-Hoop Coordination Geometry in a Dy Dimer

Spin state behavior of iron(II)/dipyrazolylpyridine complexes. New insights from crystallographic and solution measurements

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)₄]⁻ Ion

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Minimal Distortion Pathways in Polyhedral Rearrangements

Cited by 390 publications

References 15 publications

Tuning of Hula-Hoop Coordination Geometry in a Dy Dimer

Tuning of Hula-Hoop Coordination Geometry in a Dy Dimer

Spin state behavior of iron(II)/dipyrazolylpyridine complexes. New insights from crystallographic and solution measurements

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)4]− Ion

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Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)₄]⁻ Ion