Leagan Gaeilge   Text Version   Display: Zoom (-) (+)   View ( Normal High contrast ) Printer Friendly  A to Z  Sitemap

SCHOOL OF CHEMISTRY

  

Dr Leigh F. Jones (MChem., PhD, MICI, MRSC) Director of the Molecular Magnetism Laboratory (MolMagLab) Career Synopsis: MChem (Hons.) with Industrial Experience (2000) and PhD (2003), University of Manchester (UK) Awarded Royal Society International Fellowship, Monash University, Australia (2004)    Australian Research Council (ARC) Fellow, Monash University, Australia (2005) Postdoctoral Research Fellow, University of Leeds, (UK) (2006-2007) Postdoctoral Research Fellow, University of Edinburgh, (UK) (2007-2008)  Lecturer in Inorganic Chemistry, NUI, Galway (2008-present)

Phone: +353-91-493462 (for internal: ext. 3462)                                                                                                     

E-mail   

Funding Opportunities 2013  

For more information on the MolMagLab click here

For the latest news from the MolMagLab click here 

Research Interests

My research is based in the field of Molecular Magnetism which details the design, synthesis and study of novel polynuclear paramagnetic materials whose properties are inherited from their parent mononuclear molecules and may be tuned by structural variation at the molecular level. More detailed descriptions of my research interests are documented below: 

1) Paramagnetic Host-Guest Materials

Supramolecular chemistry has rapidly become a vast and multidisciplinary field with applications including catalysis, anion sensing recognition, gas sequestration / storage and species transportation towards drug delivery, and consequently is of interest to scientists of wide ranging disciplines. One particularly interesting facet of supramolecular chemistry concerns the expression of high degrees of local and extended topological control onto a molecule (e.g. a host unit) in terms of its partaking in intermolecular interactions with other species (e.g. a guest molecule). This is achieved via careful structural manipulation of these molecules (and molecular assemblies) giving rise to complex molecular architectures possessing targeted synergic chemical and physical properties. Although supramolecular host-guest chemistry has been readily exhibited and widely reported with a vast array of organic receptor moieties, the engagement of magnetically interesting inorganic host units is still relatively rare and is one important facet to research in the Jones laboratory.

With this in mind we has recently reported the synthesis and characterization of a family of ferromagnetic planar disc [M7] (M = Ni2+, Zn2+) complexes which possess double-bowl metallocalix[6]arene topologies and themselves exhibit host-guest behaviour allowing direct comparison to supramolecular calix[n]arene behaviour. Each member exhibits a double-bowl pseudo metallocalix[6]arene topology whereby the individual [M7] units form molecular host cavities which are able to accommodate various guest molecules (MeCN, MeNO2 and MeOH).

 

Molecular structures of a typical host-guest [M7] complex (this is a [Zn7] analogue) viewed perpendicular and parallel to the [M7] plane respectively. Colour code: Zn = light blue, O =" " red, N = dark blue, C = silver.

(left) Crystal structure of a host [Zn7].2MeOH disc accommodating two methanol (MeOH) guest molecules (right) Space-fill representation of the unit cell in [Zn7].2MeOH.   

2) Single-Molecule Magnets (SMMs) and Paramagnetic complexes

An important subgroup of this large research field are Single-Molecular Magnets (SMMs) which are discrete polymetallic transition metal complexes and are distinguished by their ability to exhibit magnetic hysteresis of molecular origin (i.e. [Mn26] below). This barrier to magnetization reversal stems from possession of large ground spin states (S) and significant and negative magnetic anisotropy parameters (D). This discovery spawned a new and exciting area of research in the fields of information storage devices, quantum computing and more recently as potential molecular spintronic devices (i.e. molecular transisitors and switches) and as magnetic coolant materials (moleCOOLs) arising from Magnetic Caloric Effects (MCE).

Crystal strucuture of the [Mn26] Single-Molecule Magnet, the largest SMM reported on publication.

3) Magnetic Coolant Materials (Magnetic refrigerants)

Magnetic refrigerants are complexes / materials capable of causing a significant decreasing in their temperature (mK) as a result of exposure to a large fluctuating magnetic field. Paramagnetic transition metal complexes which posses extremely large ground states (S) and negligible zero-field splitting parameters (D) may as a result exhibit the Magnetic Caloric Effect and are prime candidates for such coolants. Recent MCE studies on high-spin paramagnetic complexes ( i.e. [Fe14], below) show that they compete well with conventionally used low T magnetic refrigerant materials (i.e. Ln(III) complexes). The application and removal of a 7 T external magnetic field on a sample of [Fe14] (in an adiabatic bath) results in a remarkable 6 K – 70 mK temperature decrease and exhibits the largest MCE of any material under 10 K to date.

The highly symmetrical [Fe14] cluster with interesting coolant properties.

4) 1, 2 and 3-D Coordination Polymers (a.k.a Metal-Organic Frameworks; MOFs) 

Although the ability of SMMs to exhibit molecular magnetic hysteresis is remarkable, this phenomenon currently only functions at temperatures approaching absolute zero.  An alternative approach would be to utilise magnetic polymers, which have significantly higher operating temperatures, but lack the immediate possibility of miniaturisation to molecular scale. 1, 2 and 3-D coordination polymers (a.k.a: metal-organic frameworks, MOFs) comprise metal centres (nodes) linked into extended arrays through rigid organic linker ligands (Fig. below (top): a Co(II) 3-D network). Our current goal is to utilise highly paramagnetic polymetallic complexes (i.e. SMMs) as building blocks in the construction of pre-designed 2 and 3-D extended architectures in order to improve their function as potential magnetic materials (Fig. below (bottom): a 1-D chain of [Mn6] SMMs).

(Top) The2-D extended network [Co(dca)2(dbtp)] (where dbtp = 1,4-di(benzotriazol-1-yl)butane). (Bottom) Crystal structure of the 1-D chain of [Mn6] Single-Molecule Magnets.

The 1-D bimetallic [Na(BiphenH2)(EtOH)3][Mn(biphen)2(3-pic)2]n ionic chain held into an linear arrangements via strong H-bonds (as represented by dashed lines).

Recent Publications

1. S. T. Meally, S. M. Taylor, E. K. Brechin, S. Piligkos and L. F. Jones. Homo- and Heterometallic Planes, Chains and Cubanes. Dalton Trans., 2013, DOI Link.
2. N. Berg, T. N. Hooper, J. Liu, C. C. Beedle, S. K. Singh, G. Rajaraman, S. Piligkos, S. Hill, E. K. Brechin and L. F. Jones. Synthetic, structural, spectroscopic and theoretical study of a Mn(III)-Cu(II) dimer containing a Jahn-Teller compressed Mn ion. Dalton Trans, 2013, 42(1), 207-216. DOI Link.  
3. E. Houton, S. M. Taylor, C. C. Beedle, J. Cano, S. Piligkos, S. Hill, A. G. Ryder, E. K. Brechin and L. F. Jones. Ferromagnetic exchange in a twisted, oxime-bridged [Mn(III)₂] dimer. Dalton Trans., 2012, 41("7), 8340-8347.  DOI Link.
4. S. T. Meally, C. McDonald, P. Kealy, S. M. Taylor, E. K. Brechin and L. F. Jones. Investigating the Solid State Hosting Qualities of Homo- and Heterovalent [Co^₇] Metallocalix[6]arenes. Dalton Trans., 2012, 41(18), 5610-5616. DOI Link.
5. N. Berg, S. M. Taylor, A. Prescimone, E. K. Brechin and L. F. Jones. Old Dog, New Tricks: 2,2'-biphenol as a bridging and book-end ligand in in discrete and extended Co(II) architectures. CrystEngComm, 2012, 14(8), 2732-2738. DOI Link  
6. N. Berg, T. Rajeshkumar, E. K. Brechin, G. Rajaraman and L. F. Jones. What controls the magnetic interaction in bis-u-alkoxo bridged Mn(III) dimers? A combined experimental and theoretical exploration. Chem. Eur. J., 2012, 18, 5906-5918.  DOI Link.
7. R. Inglis, C. Milios, L. F. Jones, S. Plilgkos, E. K. Brechin. Twisted Molecular Magnets. Chem. Commun., ( Feature Article): 2012, 48, 181-190. DOI Link
8. R. Inglis, E. Houton, J. Liu, A. Prescimone, J. Cano, S. Piligkos, S. Hill, L. F. Jones, E. K. Brechin., Accidentally on purpose: Construction of a ferromagnetic, oxime based [Mn(III)2] dimer. Dalton Trans., 2011, 40, 9999-10006. DOI Link. 
9. N. Berg and L. F. Jones, A Series of Alternating Na+ / M3+ (M = Mn, Fe) Covalent and Ionic Chains. CrystEngComm., 2011, 13(17), 5510-5518.  DOI Link.
10. N. Berg and L. F. Jones. Alternating Na/Mn Covalent and Ionic Chains. CrystEngComm., 2010, 12(11), 3518-3521.  DOILink
11. S. T. Meally, C. McDonald, G. Karotsis, G. S. Papaefstathiou, E. K. Brechin, P. W. Dunne, P. McArdle, N. P. Power, L. F. Jones. A Family of Double-Bowl Pseudo Metallocalix[6]arene Discs. Dalton Trans., (Special Issue on Molecular Magnetism): 2010, 39, 4809–4816. DOILink
12. Hot Article: S. T. Meally, G. Karotsis, E. K. Brechin, G. S. Papaefstathiou, P. W. Dunne, P. McArdle, L. F. Jones., Planar [Ni7] Discs as Double-Bowl, Pseudo Metallocalix[6]arene Host Cavities. CrystEngComm., 2010, 12, 59-63. DOILink
13. S.T. Meally, K. Mason, E.K. Brechin, A.G. Ryder, and L. F. Jones., A F-bridged Molecular Square.  Chem. Commun., 2009, 7024-7026. DOILink
14. L. F. Jones, C. A. Kilner, M. A. Halcrow., A Cobalt Metallocrown Anion Host with Guest Dependent Redox Activity., Chem. Eur. J., 2009, 15, 4667-4675. DOI Link.
15. L. F. Jones, A. Prescimone, M. Evangelisti, E. K. Brechin. 1D Chains from Mn6 Single-Molecule Magnets, Chem. Commun., 2009, 2023-2025. DOI Link.
16. Hot Article: R. Inglis, L. F. Jones, C. J. Milios, S. Datta, A. Collins, S. Parsons, W. Wernsdorfer, S. Hill, S. P. Perlepes, S. Piligkos, E. K. Brechin. Attempting to Understand (and Control) the Relationship between Structure and Magnetism in an Extended Family of Mn6 Single-Molecule Magnets. Dalton Trans., 2009, 3403-3412. DOI Link.
17. R. Inglis, S. M. Taylor, L. F. Jones, G. S. Papaefstathiou, S. P. Perlepes, S. Datta, S. Hill, W. Wernsdorfer, E. K. Brechin., Twisting, Bending, Stretching: Strategies for Making Ferromagnetic Triangles. Dalton Trans., 2009, 42, 9157-9168. DOI Link.  
18. R. T. W. Scott, L. F. Jones, I. S. Tidmarsh, B. Breeze, R. H. Laye, J. Wolowska, D. J. Stone, A. Collins, S. Parsons, W. Wernsdorfer, G. Aromi, E. J. L. McInnes, E. K. Brechin., Ferromagnetic NiII discs., Chem. Eur. J., 2009, 15, 12389-12398. DOI Link.
19. L. F. Jones, R. Inglis, Martyn E. Cochrane, K. Mason, A. Collins, S. Parsons, S. P. Perlepes, E. K. Brechin. New Structural Types and Different Oxidation Levels in the Family of Mn6-oxime Single-Molecule Magnets, Dalton Trans, 2008, 6205-6210. DOI Link.
20. L. F. Jones, Constantinos J. Milios, A. Prescimone, M. Evangelisti, Euan K. Brechin, Switching pairwise Exchange to Enhance SMM Properties., C. R. Chemie, 2008, 11, 1175-1181.  DOI Link.

   

• Disclaimer
• Privacy
• Copyright
• Accessibility