Head of Discipline for Chemistry

Valeria Arrighi

 

Staff by Sections

Inorganic Chemistry

Alan Welch

Jan-Willem Bos

James Cameron

Scott Dalgarno

Gareth Lloyd

Stuart Macgregor

Stephen Mansell 

Ruaraidh McIntosh

Organic Chemistry

Dave Adams

Euan Brown

Graeme Barker

Magnus Bebbington

Nicola Howarth

Arno Kraft

Ai-Lan Lee

Nick Leslie

Kevin McCullough

Colin Rickman

Filipe Vilela

Physical Chemistry

Ken McKendrick

Valeria Arrighi

David Bucknall

Matt Costen

Stuart Greaves

Maciej Gutowski

Martin McCoustra

N Hendrik Nahler

Martin Paterson

Experimental Officers and Administrative Staff

Dave Ellis

Georgina Rosair

Placement Coordinators

Industrial:  Scott Dalgarno

Honorary and Emeritus Staff

John Parker

Joe Pfab

Stuart Macgregor

BSc, PhD, FRSC

Director of Research

Telephone
+44 (0)131 451 8031
Email
s.a.macgregor@hw.ac.uk
Address
Room 2.16
William Perkin Building
Heriot-Watt University
Roles and responsibilities
  • Director of Research, School of Engineering and Physical Sciences
Research

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= PR3 metallophosphoranes, [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.

 

 

 

 

 

 

 

Selected publications

Up-to-date publications are listed on this research profile.

Further information

 Group Website