Dr John Slattery

01904 322610
E-mail: john.slattery@york.ac.uk

Ionic liquids, organometallic chemistry, computational chemistry and main-group chemistry

We are interested in using a rational “bottom-up” approach for the design of new molecular systems with particular features or functionality. This may be with an application in mind e.g. as ionic liquids, catalysts, electrolytes in battery and fuel cells or in photovoltaic/electroluminescent devices. Alternatively, it may involve the synthesis and study of new species of fundamental interest. In addition to the study of new species, we are actively involved in mechanistic studies to understand the mode of action of currently available homogeneous catalysts with a view to improving their activity using combined experimental and computational methods.

This work involves many different aspects of chemistry including synthetic main-group chemistry, ionic liquids, organometallic chemistry, computational chemistry and catalysis.

We are always interested to hear from enthusiastic and tallented students and post-doctoral researchers looking to join the group (for PhD projects, post-doctoral positions, MChem research projects, Erasmus placements etc.). Please contact John Slattery (john.slattery@york.ac.uk) to discuss currently available projects.

Ionic Liquids

Ionic liquids (ILs) are an interesting class of salts with surprisingly low melting points. They are often liquid at room temperature, which is remarkable considering the high melting points of classical inorganic salts such as NaCl (m.p. 800° C). ILs are usually composed of a relatively large organic cation in combination with a complex anion e.g. [EMIM]+[BF4] (below).

1-ethyl-3-methylimidazolium cation (left) and tetrafluoroborate anion (right)
The 1-ethyl-3-methylimidazolium cation (left) and tetrafluoroborate anion (right) form one of the more common room-temperature ionic liquids (often abbreviated [EMIM][BF4]).

ILs are currently attracting considerable attention, as their unique properties make them suitable for a wide range of applications. There is also considerable scope for modification of the cation and/or anion structure to tune the properties of an IL. We have recently developed some simple techniques to predict the physical properties of these materials. This promises to simplify the design of new ILs with particular properties tuned to specific applications. In recent collaborations with Prof. Ian Fairlamb (York), Prof. Ken McKendrick (Heriot-Watt) and Prof. Tim Minton (Montana State) we have designed "doped" ionic liquids with alkene functionality for Pd catalysis and probed the surface structure of ionic liquids using reactive oxygen atoms. We are also involved in an ongoing collaboration with Prof. Duncan Bruce (York) investigating the synthesis of new liquid-crystalline ionic liquids (LCILs) and their use as structured reaction media for pericyclic organic reactions.

Main Group Chemistry

Weakly coordinating ions such as those found in ILs also have applications in the stabilisation of reactive anions or cations of fundamental interest. One of our main goals is the synthesis of new and unusual main-group-element-containing ions. For example, we were able to investigate the coordination chemistry of low-valent gallium cations with very weak ligands by combining these cations with weakly coordinating anions (WCAs). These chemically robust, weakly basic anions do not compete with the ligands for metal coordination and also do not decompose in the presence of very electrophilic cations. Our WCA salts of Ga+ have allowed us to gain access to chemistry that was previously impossible using conventional sources of Ga(I) - for example the synthesis of the first example of a Ga(I)-phosphine complex [Ga(PPh3)3]+[WCA]-.

crystal structure of an arene complex of Ga+ in combination with one of the best WCAs

The crystal structure of an arene complex of Ga+ in combination with one of the best WCAs [Al(OC(CF3)3)4]. Although the WCA is very weakly nucleophilic, some long range anion–cation interactions between Ga and F atoms are still present – there is no such thing as a non-coordinating anion!

Computational Chemistry

Our work often involves the use of quantum chemical techniques alongside synthetic studies. Ab initio and density functional theory (DFT) methods can help in the interpretation of synthetic results e.g. by simulation of IR/Raman and NMR spectra, visualisation of molecular orbitals and investigation of reaction mechanisms. We have recently used DFT methods in combination with experimental studies to probe the mechanism of alkyne to vinylidene conversions at Ru and Rh centres. Theoretical studies were able to reproduce the experimental findings and give extra insight into the mechanism in the Rh system, including a survey of substituent effects that would have been very time consuming to perform experimentally. We were also able to identify a new mechanism in C-H activation chemistry, the ligand-assisted proton shuttle (LAPS) mechanism, where the ligand periphery around the metal centre is as important for the mechanism as the metal itself. This synergy between computational and experimental studies is key to a collaboration between our group and that of Jason Lynam, which aims to better understand and ultimately to design better homogeneous catalysts.

PE surface for the alkyne to vinylidene transformation at Rh.

The potential energy surface for the alkyne to vinylidene transformation at Rh(PR3)2Cl. The simplest system studied is shown, but a variety of different substituents on the alkyne and phosphine ligands were investigated.

In collaboration with the group of Bernhard Breit in Freiburg, Germany we have also used DFT studies to examine the structural chemistry of supramolecular metallopeptide catalysts. These intriguing complexes incorporate phosphine ligands that mimic nature using various non-covalent interactions to self assemble chiral bidentate ligands with defined strutures.

Selected References

  • Outer-sphere electrophilic fluorination of organometallic complexes
    Lucy M. Milner, Natalie E. Pridmore, Adrian C. Whitwood, Jason M. Lynam, and John M. Slattery, J. Am. Chem. Soc., 2015, 137, 10753-10759.
  • Access to novel fluorovinylidene ligands via exploitation of outer-sphere electrophilic fluorination: new insights into C–F bond formation and activation
    Lucy M. Milner, Lewis M. Hall, Natalie E. Pridmore, Matthew K. Skeats, Adrian C. Whitwood, Jason M. Lynam and John M. Slattery, Dalton Trans., 2016, advance article available online.
  • Structure of Amido-Pyridinium Betaines: Persistent Intermolecular C-H•••N Hydrogen Bonding in Solution
    Robert J. Thatcher, David G. Johnson, John M. Slattery and Richard E. Douthwaite, Chem. Eur. J., 2016, advance article available online.
  • Mechanistic insight into the ruthenium-catalysed anti-Markovnikov hydration of alkynes using a self-assembled complex: a crucial role for ligand-assisted proton shuttle processes
    Bernhard Breit, Urs Gellrich, Timothy Li, Jason M. Lynam, Lucy M. Milner, Natalie E. Pridmore, John M. Slattery and Adrian C. Whitwood, Dalton Trans., 2014, 43, 11277-11285.
  • Ruthenium-Mediated C−H Functionalization of Pyridine: The Role of Vinylidene and Pyridylidene Ligands
    David G. Johnson, Jason M. Lynam, Neetisha S. Mistry, John M. Slattery, Robert J. Thatcher, and Adrian C. Whitwood, J. Am. Chem. Soc., 2013, 135, 2222−2234.
  • How Lewis acidic is your cation? Putting phosphenium ions on the fluoride-ion affinity scale
    John M. Slattery and Sharifa Hussein,  Dalton Trans., 2012, 41, 1808–1815. {Selected as a "Hot Article" and featured on the Dalton Transactions Blog (http://blogs.rsc.org/dt/2011/12/20/are-there-anymore-phosphenium-free-ions/)}
  • Insights into the intramolecular acetate-mediated formation of ruthenium vinylidene complexes: a ligand-assisted proton shuttle (LAPS) mechanism.
    D. G. Johnson, J. M. Lynam, J. M. Slattery and C. E. Welby, Dalton Trans., 2010, 39, 10432–10441. (Selected as a "Hot Article")
  • A simple route to univalent gallium salts of weakly coordinating anions.
    John M. Slattery, Alexander Higelin, Thomas Bayer, Ingo Krossing, Angew. Chem. Int. Ed., 2010, 49 , 3228–3231. (Selected as a “VIP” article and provided the inside cover artwork for the issue.)
  • Ion-tagged pi-acidic alkene ligands promote Pd-catalysed allyl–aryl couplings in an ionic liquid.
    Patrick S. Bäuerlein, Ian J. S. Fairlamb, Amanda G. Jarvis, Adam F. Lee, Christian Müller, John M. Slattery, Robert J. Thatcher, Dieter Vogt and Adrian C. Whitwood, Chem. Commun., 2009, 5734–5736.
  • Supramolecular bidentate ligands by metal-directed in situ formation of antiparallel beta-sheet structures and application in asymmetric catalysis.
    A C Laungani, J M Slattery, I Krossing and B Breit,  Chem Eur J, 2008, 14, 4488–4502. (Provided the inside cover artwork for the issue.)
  • How to predict the physical properties of ionic liquids: a volume-based approach.
    J M Slattery, C Daguenet, T Schubert and I Krossing, Angew. Chem Int Ed Engl, 2007, 46, 5384–5388. (Selected as a “Hot Paper”.)
  • Why are ionic liquids liquid? A simple explanation based on lattice and solvation energies.
    I Krossing, J M Slattery, C Daguenet, P J Dyson, A Oleinikova and H. Weingärtner, J Am Chem Soc, 2006, 128, 13427–13434. (A “Hot Paper” – based on citations. Highlighted as an “Editors Choice” in Science, 2006, 314, 19 and in Anal Chem, 2006, 78, 7906.)