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Research interests

Computational Organometallic Chemistry

Research uses computational chemistry to model reaction mechanisms in transition metal organometallic chemistry. Methods employed include density functional theory, hybrid QM/MM calculations and molecular dynamics. We aim to understand challenging bond activation processes (C-H and C-F bond cleavage), rationalise unusual reactivity patterns and model multi-step catalytic cycles. Research is usually carried out in close collaboration with experimental chemists.

1. Ambiphilic Metal-Ligand Assisted (AMLA) C-H Activation

We have developed the concept of Ambiphilic Metal-Ligand Assisted (AMLA) C-H activation. In this process an agostic interaction to an unsaturated metal centre combines with H-bonding to a basic co-ligand to facilitate C-H bond cleavage. With aromatic C-H activation at [Pd(OAc)2] this mechanism supersedes the long-proposed Wheland-type intermediate.  AMLA can account for facile C-H bond cleavage of both e--deficient and e--rich aromatic substrates at a range of late transition metal centres.

Figure 1. Computed agostic Intermediate in the AMLA-6 C-H Activation of dimethylbenzylamine at [Pd(OAc)2].

2. Metallophosphoranes and Aromatic C-F Bond Activation

We have defined novel ligand-assisted mechanisms for breaking the strong C-F bond of fluoroaromatics. This process involves nucleophilic attack by an e--rich metal centre with addition of a C-F bond over the M-L moiety, where L can be PR3, SiR3 or BR2. For L= PR3metallophosphoranes, [LnM-(PFR3)], are formed as intermediates or transition states. Metallophosphoranes also play a role in the unusual M-F/P-R exchange reactions, such as the interconversion of [RhF(PPh3)3] to [Rh(Ph)(PFPh2)(PPh3)2].

 

Figure 2. The central role of metallophosphoranes in phosphine-assisted C-F bond activation and F/R exchange processes.

3. Ruthenium N-Heterocyclic Carbene (NHC) Complexes in Catalysis

NHC ligands often confer enhanced reactivity on metal complexes. An example is the hydrodefluorination of C6F5H to give 1,2-C6F4H2 catalysed by [Ru(H)2(CO)(NHC)(PR3)2] species. Calculations show this unusual ortho-selectivity arises from a nucleophilic attack mechanism where the hydride ligand (and not the metal) acts as the reacting species. Calculations also aim to understand the stability of NHC ligands towards metal-based decomposition reactions such as C-H, C-C and C-N activation.

 

Figure 3. Nucleophilic attack of a hydride ligand at the ortho position of C6F5H.

Roles & Responsibilities

Research Group Contact Details

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  • 2 Similar Profiles
phosphine Chemical Compounds
Chemical activation Chemical Compounds
Carbon Monoxide Chemical Compounds
Metals Chemical Compounds
Ligands Chemical Compounds
Discrete Fourier transforms Chemical Compounds
Rhodium Chemical Compounds
Ruthenium Chemical Compounds

Co Author Network Recent external collaboration on country level. Dive into details by clicking on the dots.

Research Output 1990 2019

A d10 Ag(i) amine-borane σ-complex and comparison with a d8 Rh(i) analogue: structures on the η1 to η2:η2 continuum

Johnson, A., Martínez-Martínez, A. J., Macgregor, S. A. & Weller, A. S., 23 Apr 2019, In : Dalton Transactions.

Research output: Contribution to journalArticle

Open Access
File
Boranes
Molecular Structure
Amines
Metals
Electrons

Base-Promoted, Remote C-H Activation at a Cationic (η5-C5Me5)Ir(III) Center Involving Reversible C-C Bond Formation of Bound C5Me5

Moreno, J. J., Espada, M. F., Campos, J., López-Serrano, J., Macgregor, S. A. & Carmona, E., 13 Feb 2019, In : Journal of the American Chemical Society. 141, 6, p. 2205-2210 6 p.

Research output: Contribution to journalArticle

phosphine
Ligands
Thermodynamics

N-Heterocyclic Carbene Non-Innocence in the Catalytic Hydrophosphination of Alkynes

Blackaby, W. J. M., Neale, S. E., Isaac, C. J., Sabater, S., Macgregor, S. A. & Whittlesey, M. K., 4 Apr 2019, In : ChemCatChem. 11, 7, p. 1893-1897 5 p.

Research output: Contribution to journalArticle

Alkynes
carbenes
alkynes
Discrete Fourier transforms
Negative ions

Room Temperature Iron-Catalyzed Transfer Hydrogenation and Regioselective Deuteration of Carbon-Carbon Double Bonds

Espinal-Viguri, M., Neale, S. E., Coles, N. T., Macgregor, S. A. & Webster, R. L., 9 Jan 2019, In : Journal of the American Chemical Society. 141, 1, p. 572-582 11 p.

Research output: Contribution to journalArticle

Hydrogenation
Carbon
Iron
Amines
Boranes

Benzoate Cyclometalation Enables Oxidative Addition of Haloarenes at a Ru(II) Center

Simonetti, M., Kuniyil, R., Macgregor, S. A. & Larrosa, I., 19 Sep 2018, In : Journal of the American Chemical Society. 140, 37, p. 11836–11847 12 p.

Research output: Contribution to journalArticle

Benzoates
Salts
Metals
Electrons

Activities 2011 2018

  • 3 Editorial activity
  • 3 Invited talk
  • 1 Membership of committee
  • 1 Membership of peer review panel

Organometallic Chemistry in Confined Spaces

Stuart Alan Macgregor (Speaker)
6 Sep 2018

Activity: Talk or presentationInvited talk

Modelling Alkane sigma-Complexes in the Solid State

Stuart Alan Macgregor (Speaker)
16 Jul 2018

Activity: Talk or presentationInvited talk

EPSRC e-Infrastructure Strategic Advisory Board (External organisation)

Stuart Alan Macgregor (Member)
1 Mar 201729 Feb 2020

Activity: MembershipMembership of committee

Modelling sigma-alkane complexes in the solid-state

Stuart Alan Macgregor (Speaker)
7 Aug 2017

Activity: Talk or presentationInvited talk

Structure and Bonding (Journal)

Stuart Alan Macgregor (Guest editor)
2016

Activity: Publication peer-review and editorial workEditorial activity