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The University of Southampton
Chemistry

Research project: Reid: s-Block complexes with soft donor ligands

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The neutral group 16 donor chalcogenoethers, ER2 (E = S, Se, Te) are generally regarded as soft, modest σ-donor ligands that form complexes readily with middle and late transition metals in low oxidation states. However, by controlling the reaction conditions and selecting the metal ion source carefully, new types of complexes containing soft chalcogenoether ligands with hard, early transition metal ions (including, for example, Ti, Zr, Hf(IV), V(IV), V(III), Nb(V), Ta(V), Cr(III), etc.) can be prepared. This opens up the opportunity to explore how these very unusual metal-ligand combinations affect the chemistry and reactivity within these unusual complexes. Similarly, neutral phosphine ligands, PR3, are ubiquitous in transition metal chemistry, owing to their capacity to tune the electronic and steric properties, and hence the reactivity, of the complexes, and to the strong σ-donor properties of the soft phosphine donor functions. This has led to wide utilisation of phosphine co-ligands in many transition metal reagents and catalysts. We have now extended this work to explore the chemistry of soft donor ligands towards alkali metal and alkaline earth cations.

Group 1 and group 2 complexes with soft donor ligands

The neutral group 16 donor chalcogenoethers, ER2 (E = S, Se, Te) are generally regarded as soft, modest σ-donor ligands that form complexes readily with middle and late transition metals in low oxidation states. However, by judicious choice of the reaction conditions and metal ion source, new types of complexes containing soft chalcogenoether ligands with hard, early transition metal ions (including, for example, Ti, Zr, Hf(IV), V(IV), V(III), Nb(V), Ta(V), W(VI), etc.) can be prepared. This opens up the opportunity to explore how these very unusual metal-ligand combinations affect the chemistry and reactivity within these unusual complexes, generating new single source reagents for materials deposition. Similarly, neutral phosphine ligands, PR3, are ubiquitous in transition metal chemistry, owing to their capacity to tune the electronic and steric properties, and hence the reactivity, of the complexes, and to the strong σ-donor properties of the soft phosphine donor functions. This has led to wide utilisation of phosphine co-ligands in many transition metal reagents and catalysts. We have now extended this work to explore the chemistry of soft donor ligands towards alkali metal and alkaline earth cations.

Notable recent contributions include developing a strategy to enable access to very elusive metal-ligand combinations by taking advantage of large, diffuse fluorinated tetra-aryl borate anions.This has led to several new classes of complexes, including unprecedented octathioether macrocyclic coordination to Na+ (Inorg. Chem. 2015, 54, 2497; doi:10.1021/acs.inorgchem.5b00156 ) and the first alkali metal cation complexes with homoleptic neutral phosphine coordination (Chem. Commun. 2015, 51, 9555; doi:10.1039/C5CC03184B ). This work is being extended to alkaline earth and f-block dications with S/Se-donor macrocyclic ligands (Dalton Trans. 2015, 44, 2953; doi:10.1039/C4DT03462G ; Dalton Trans. 2012, 42, 89; doi:10.1039/C2DT31692G ).

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Related research groups

Functional Inorganic, Materials and Supramolecular Chemistry
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