The interplay between steric repulsions and metal-metal bonding in [Ru 2(μ-Cl)3(PR3)6]z+, R = H, Me, Et, z = 1, 2, 3: A hybrid QM/MM study

Sushilla Z. Knottenbelt; John E. McGrady; Graham A. Heath

doi:10.1039/b208530e

The interplay between steric repulsions and metal-metal bonding in [Ru ₂(μ-Cl)₃(PR₃)₆]^z+, R = H, Me, Et, z = 1, 2, 3: A hybrid QM/MM study

Sushilla Z. Knottenbelt, John E. McGrady^*, Graham A. Heath

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

3 Citations (Scopus)

Abstract

The hybrid quantum/molecular mechanics methodology is used to examine the interplay between metal-metal bonding and steric effects in a series of isostructural redox-related ruthenium dimers. Potential energy surfaces for the various electronic states arising from (d⁶d⁶) (1 +), (d⁵d⁶) (2+) and (d⁵d⁵) (3+) configurations are explored. Somewhat counterintuitively, the bulky groups on the phosphine ligands are found to have most effect when the Ru-Ru bonding is strongest. The origin of this trend has been traced to the nature of the steric interactions, which are largely between the bridging halides and the substituents on the phosphine. As the Ru-Ru bond contracts, a concertina-like motion displaces the halides away from the trigonal axis and towards the phosphine substituents. The resulting competition between Ru-Ru bonding and steric repulsions means that varying the bulk of the phosphine provides an efficient mechanism for tuning or even completely eliminating the metal-metal bond.

Original language	English
Pages (from-to)	227-232
Number of pages	6
Journal	Dalton Transactions
Issue number	2
DOIs	https://doi.org/10.1039/b208530e
Publication status	Published - 21 Jan 2003

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title = "The interplay between steric repulsions and metal-metal bonding in [Ru 2(μ-Cl)3(PR3)6]z+, R = H, Me, Et, z = 1, 2, 3: A hybrid QM/MM study",

abstract = "The hybrid quantum/molecular mechanics methodology is used to examine the interplay between metal-metal bonding and steric effects in a series of isostructural redox-related ruthenium dimers. Potential energy surfaces for the various electronic states arising from (d6d6) (1 +), (d5d6) (2+) and (d5d5) (3+) configurations are explored. Somewhat counterintuitively, the bulky groups on the phosphine ligands are found to have most effect when the Ru-Ru bonding is strongest. The origin of this trend has been traced to the nature of the steric interactions, which are largely between the bridging halides and the substituents on the phosphine. As the Ru-Ru bond contracts, a concertina-like motion displaces the halides away from the trigonal axis and towards the phosphine substituents. The resulting competition between Ru-Ru bonding and steric repulsions means that varying the bulk of the phosphine provides an efficient mechanism for tuning or even completely eliminating the metal-metal bond.",

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AU - McGrady, John E.

AU - Heath, Graham A.

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AB - The hybrid quantum/molecular mechanics methodology is used to examine the interplay between metal-metal bonding and steric effects in a series of isostructural redox-related ruthenium dimers. Potential energy surfaces for the various electronic states arising from (d6d6) (1 +), (d5d6) (2+) and (d5d5) (3+) configurations are explored. Somewhat counterintuitively, the bulky groups on the phosphine ligands are found to have most effect when the Ru-Ru bonding is strongest. The origin of this trend has been traced to the nature of the steric interactions, which are largely between the bridging halides and the substituents on the phosphine. As the Ru-Ru bond contracts, a concertina-like motion displaces the halides away from the trigonal axis and towards the phosphine substituents. The resulting competition between Ru-Ru bonding and steric repulsions means that varying the bulk of the phosphine provides an efficient mechanism for tuning or even completely eliminating the metal-metal bond.

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The interplay between steric repulsions and metal-metal bonding in [Ru ₂(μ-Cl)₃(PR₃)₆]^z+, R = H, Me, Et, z = 1, 2, 3: A hybrid QM/MM study

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