Influence of the Ligand on the Coupling between the Metal-Based Electrons in Face-Shared [M2X9]3- (M = Mo, W; X = F, Cl, Br, I) Systems

Cavigliasso, Germán; Stranger, Robert

doi:10.1021/ic026291p

Cited by 11 publications

(13 citation statements)

References 25 publications

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“…6. Strong linear correlations have been obtained for all groups considered, as previously observed for face-shared [M 2 X 9 ] zÀ series involving a variety of metals and ligands [19,27]. The dashed line corresponds to…”

Section: Through To D 3 D 3 Configurations and Subsequently Decrsupporting

confidence: 80%

Periodic trends in metal–metal bonding in edge-shared [M2Cl10]4− systems

Cavigliasso¹,

Yu²,

Stranger³

2007

Polyhedron

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Periodic trends in metal-metal interactions in edge-shared [M 2 Cl 10 ] 4À systems, involving the transition metals from groups 4 through 8 and electronic configurations ranging from d 1 d 1 through d 5 d 5 , have been investigated by calculating metal-metal bonding and spinpolarization (exchange) effects using density functional theory. The trends found in this study are compared with those for the analogous face-shared [M 2 Cl 9 ] 3À systems reported in earlier work. Strong linear correlations between the metal-metal bonding and spin-polarization terms have been obtained for all groups considered. In general, spin polarization and electron localization are predominant in 3d-3d species whereas electron delocalization and metal-metal bonding are favoured in 5d-5d species, with more variable results observed for 4d-4d systems. As previously found for face-shared [M 2 Cl 9 ] 3À systems, the strong correlations between the metal-metal bonding and spin polarization energy terms can be related to the fact that both properties appear to be similarly affected by the changes in the metal orbital properties and electron density occurring within the d n d n groups. A significant difference between the face-shared and edge-shared systems is that while the 4d metals in the former show a strong tendency for delocalized metal-metal bonded structures, the edge-shared counterparts display much greater variation with both metal-metal bonded and weakly coupled complexes observed. The tendency for weaker metal-metal interactions can be traced to the inability of the edge-shared bridging structure to accommodate the smaller metalmetal distances required for strong metal-metal bonding.

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Section: Through To D 3 D 3 Configurations and Subsequently Decrsupporting

confidence: 80%

Periodic trends in metal–metal bonding in edge-shared [M2Cl10]4− systems

Cavigliasso¹,

Yu²,

Stranger³

2007

Polyhedron

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“…An explanation for these qualitative trends can be given in terms of how the changes in the metal properties affect the two energetic factors. 16, 18 As a group is descended, the greater size of the metal ions and the more diffuse nature of the metal d orbitals lead to an enhancement in the metal-metal orbital overlap and therefore metal-metal bonding, but to a reduction in spin polarization as a consequence of the increased average interelectronic separation.…”

Section: General Trends For D N D N [M 2 Cl 9 ] 3− Systemsmentioning

confidence: 99%

Periodic trends in metal–metal interactions in face-shared [M₂Cl₉]^z−systems

2006

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The periodic trends in metal-metal interactions in even-electron and mixed-valence [M2Cl9]z- face-shared systems, involving transition metals in Groups 4 to 8 and electronic configurations ranging from d1d1 through to d5d5 and from d1d2 through to d4d5, have been investigated by calculating metal-metal bonding and spin polarization (exchange) effects using density functional theory. These two terms are in opposition to one another and their relative difference determines the extent to which the metal-based electrons are delocalized and thus the degree of metal-metal bonding. Remarkably strong linear correlations between the two terms, and between each term and the square of the spin density on the metal centres, have been obtained for all group and period series considered, and are discussed in terms of their dependence on the metal orbital properties and electron density.

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“…Closed energy cycles for the high-spin/low-spin and localization/delocalization equilibria in [M 2 Cl 9 ] 3- species are defined in sections b and c of Figure , respectively. In our previous studies , of [M 2 X 9 ] z - systems, we have identified two factors as central to determining the strength of the metal−metal interactions. These are the overlap between the orbitals on opposite metal centers, and the spin polarization energy associated with the presence of unpaired electron density on the metal sites.…”

Section: Resultsmentioning

confidence: 99%

Density Functional Investigation of Metal−Metal Interactions in d⁴d⁴ Face-Shared [M₂Cl₉]³^- (M = Mn, Tc, Re) Systems

Cavigliasso

Stranger

2004

Inorg. Chem.

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The molecular and electronic structures of the d(4)d(4) face-shared [M(2)Cl(9)](3)(-) (M = Mn, Tc, Re) dimers have been calculated by density functional methods in order to investigate metal-metal bonding in this series. The electronic structures of these systems have been analyzed using potential energy curves for the broken-symmetry and other spin states arising from the various d(4)d(4) coupling modes, and closed energy cycles have been utilized to identify and quantify the parameters which are most important in determining the preference for electron localization or delocalization and for high-spin or low-spin configurations. In [Tc(2)Cl(9)](3)(-) and [Re(2)Cl(9)](3)(-), the global minimum has been found to be a spin-triplet state arising from the coupling of metal centers with low-spin configurations, and characterized by delocalization of the metal-based electrons in a double (sigma and delta(pi)) bond with a metal-metal separation of 2.57 A. In contrast, high-spin configurations and electron localization are favored in [Mn(2)Cl(9)](3)(-), the global minimum for this species being the ferromagnetic S = 4 state with a rather long metal-metal separation of 3.43 A. These results are consistent with metal-metal overlap and ligand-field effects prevailing over spin polarization effects in the Tc and Re systems, but with the opposite trend being observed in the Mn complex. The ground states and metal-metal bonding observed for the d(4)d(4) systems in this study parallel those previously found for the analogous d(2)d(2) complexes of V, Nb, and Ta, and can be rationalized on the basis that the d(4)d(4) dimer configuration is the hole equivalent of the d(2)d(2) configuration.

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Influence of the Ligand on the Coupling between the Metal-Based Electrons in Face-Shared [M₂X₉]³^- (M = Mo, W; X = F, Cl, Br, I) Systems

Cited by 11 publications

References 25 publications

Periodic trends in metal–metal bonding in edge-shared [M2Cl10]4− systems

Periodic trends in metal–metal bonding in edge-shared [M2Cl10]4− systems

Periodic trends in metal–metal interactions in face-shared [M₂Cl₉]^z−systems

Density Functional Investigation of Metal−Metal Interactions in d⁴d⁴ Face-Shared [M₂Cl₉]³^- (M = Mn, Tc, Re) Systems

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Influence of the Ligand on the Coupling between the Metal-Based Electrons in Face-Shared [M2X9]3- (M = Mo, W; X = F, Cl, Br, I) Systems

Cited by 11 publications

References 25 publications

Periodic trends in metal–metal bonding in edge-shared [M2Cl10]4− systems

Periodic trends in metal–metal bonding in edge-shared [M2Cl10]4− systems

Periodic trends in metal–metal interactions in face-shared [M2Cl9]z−systems

Density Functional Investigation of Metal−Metal Interactions in d4d4 Face-Shared [M2Cl9]3- (M = Mn, Tc, Re) Systems

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Influence of the Ligand on the Coupling between the Metal-Based Electrons in Face-Shared [M₂X₉]³^- (M = Mo, W; X = F, Cl, Br, I) Systems

Periodic trends in metal–metal interactions in face-shared [M₂Cl₉]^z−systems

Density Functional Investigation of Metal−Metal Interactions in d⁴d⁴ Face-Shared [M₂Cl₉]³^- (M = Mn, Tc, Re) Systems