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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

Fingerprint Dive into the research topics where Stuart Alan Macgregor is active. These topic labels come from the works of this person. Together they form a unique fingerprint.

  • 1 Similar Profiles
phosphine Chemical Compounds
Chemical activation Chemical Compounds
Carbon Monoxide Chemical Compounds
Metals Chemical Compounds
Ligands Chemical Compounds
Discrete Fourier transforms Chemical Compounds
Density functional theory 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 Career in Catalysis: Odile Eisenstein

Balcells, D., Clot, E., Macgregor, S. A., Maseras, F. & Perrin, L., 17 Oct 2019, In : ACS Catalysis. p. 10375-10388 14 p.

Research output: Contribution to journalReview article

Catalysis
Computational chemistry
Catalytic oxidation
Coordination Complexes
Alkenes

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. 48, 26, p. 9776-9781 6 p.

Research output: Contribution to journalArticle

Open Access
File
Boranes
Molecular structure
Electronic structure
Amines
Metals

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
Chemical activation
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

Reductive Elimination at Carbon under Steric Control

Tolentino, D. R., Neale, S. E., Isaac, C. J., MacGregor, S. A., Whittlesey, M. K., Jazzar, R. & Bertrand, G., 26 Jun 2019, In : Journal of the American Chemical Society. 141, 25, p. 9823-9826 4 p.

Research output: Contribution to journalArticle

Carbon
Metals
Chemical activation
Transition metals
carbene

Prizes

Ludwig Mond Award

Stuart Alan Macgregor (Recipient), 1 May 2019

Prize: Prize (including medals and awards)

Inorganic Chemistry

Activities 2011 2019

Structure and Bonding (Journal)

Stuart Alan Macgregor (Editorial board member)
1 Jan 201931 Dec 2022

Activity: Publication peer-review and editorial workEditorial activity

Faraday Discussions

Stuart Alan Macgregor (Invited speaker)
2 Sep 2019

Activity: Participating in or organising an eventParticipation in conference

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

44th International Conference on Coordination Chemistry (ICCC 2020) (Event)

Stuart Alan Macgregor (Chair)
1 Nov 201831 Jul 2020

Activity: MembershipMembership of committee