Dr Timothy Easun
Royal Society University Research Fellow
- Email:
- easuntl@cardiff.ac.uk
- Telephone:
- +44 (0)29 2087 4066
Dr Easun's research targets the use of photochemistry to control molecular flow in microporous materials in order to make functional nanofluidic devices. This involves the functionalisation of crystalline porous materials, specifically using thermally and photochemically active components to control framework properties and direct guest uptake and release.
The key concepts that underpin this research are those of supramolecular photochemistry, nanofluidics, time-resolved spectroscopies, photocrystallography and microporous materials with nanoscale pores and channels.
The work is focussed on two main areas: the surface modification of metal-organic framework (MOF) crystals to photogate access to and from their pores and the design of new MOF linkers that change shape on photoirradiation. These projects require the design, synthesis and characterisation of photoactive molecules, studied by ultrafast time-resolved and spatially-resolved spectroscopies, coupled with new and emerging photocrystallographic techniques that allow us to understand in detail the behaviour of these molecules in single crystals.
Selected publications:
PNAS, 2017, 114, 12, 3056-3061: "Tailoring porosity and rotational dynamics in a series of octacarboxylate metal-organic frameworks".
J. Am.Chem. Soc., 2016, 138 (20), 6352-6355: “Proton Conduction in a Phosphonate-Based Metal–Organic Framework Mediated by Intrinsic “Free Diffusion inside a Sphere”
J. Mater. Chem A, 2016, 4, 6714: “The lighter side of MOFs: structurally photoresponsive metal–organic frameworks”. [Invited review for 2016 “Emerging Investigators” special issue]
Chemical Science, 2014, 5, 539: “Modification of Coordination Networks Through a Photoinduced Charge Transfer Process”
Msci Chemistry (with ERASMUS semester at the Università degli Studi di Sassari, Italy), University of Nottingham (1998-2002); PhD, University of Sheffield (2003-2007, Prof. Mike Ward); Postdoctoral Research Fellow, University of Nottingham (2007-2010, Prof. Mike George); Inorganic Teaching Fellow, University of Nottingham (2010-2011); Senior Research Officer, University of Nottingham (2011-2015, Prof. Martin Schröder, Dean of the Faculty of Science). Appointed Cardiff University Research Fellow 2015 and awarded Royal Society University Research Fellowship in the same year.
Professional memberships
Member of the Royal Society of Chemistry, the American Chemical Society, the Infrared & Raman Discussion Group, the British Crystallographic Association, and Early Career Panel Member of the EPSRC Directed Assembly Grand Challenge Network.
2019
- Smith, G. L.et al. 2019. Reversible coordinative binding and separation of sulfur dioxide in a robust metal-organic framework with open copper sites. Nature Materials (10.1038/s41563-019-0495-0)
- Asghar, A.et al. 2019. Efficient one-pot synthesis of a hexamethylenetetramine-doped Cu-BDC metal-organic framework with enhanced CO2 adsorption. Nanomaterials 9(8), article number: 1063. (10.3390/nano9081063)
- Humby, J.et al. 2019. Host-guest selectivity in a series of isoreticular metal-organic frameworks: observation of acetylene-to-alkyne and carbon dioxide-to-amide interactions. Chemical Science 10(4), pp. 1098-1106. (10.1039/C8SC03622E)
2018
- Pietrzak, B.et al. 2018. Nurturing connections to the environment. Science 362(6417), pp. 886. (10.1126/science.aav9402)
- Easun, T. L. and Nevin, A. C. 2018. Metal nodes and metal sites in metal-organic frameworks. In: Patmore, N. J. and Elliott, P. I. P. eds. Organometallic Chemistry: Volume 42., Vol. 42. SPR - Organometallic Chemistry, pp. 54-79., (10.1039/9781788010672-00054)
- Godfrey, H. G. W.et al. 2018. Ammonia storage by reversible host-guest site exchange in a robust metal-organic framework. Angewandte Chemie International Edition 57(45), pp. 14778-14781. (10.1002/anie.201808316)
- Mitra, T.et al. 2018. Characterisation of redox states of metal-organic frameworks by growth on modified thin-film electrodes. Chemical Science 9(31), pp. 6572-6579. (10.1039/C8SC00803E)
2017
- Jones, C. L.et al. 2017. Investigating the geometrical preferences of a flexible benzimidazolone-based linker in the synthesis of coordination polymers. Royal Society Open Science 4(12), article number: 171064. (10.1098/rsos.171064)
- Tansell, A. J., Jones, C. L. and Easun, T. L. 2017. MOF the beaten track: unusual structures and uncommon applications of metal-organic frameworks. Chemistry Central Journal 11, article number: 100. (10.1186/s13065-017-0330-0)
- Laybourn, A.et al. 2017. Metal-organic frameworks in seconds via selective microwave heating. Journal of Materials Chemistry A 16, pp. 7333-7338. (10.1039/C7TA01493G)
- Moreau, F.et al. 2017. Tailoring porosity and rotational dynamics in a series of octacarboxylate metal-organic frameworks. Proceedings of the National Academy of Sciences of the United States of America 114(12), pp. 3056-3061. (10.1073/pnas.1615172114)
- Lu, Z.et al. 2017. Modulating supramolecular binding of carbon dioxide in a redox-active porous metal-organic framework. Nature Communications 8, pp. 14212. (10.1038/ncomms14212)
- Moreau, F.et al. 2017. Unravelling exceptional acetylene and carbon dioxide adsorption within a tetra-amide functionalized metal-organic framework. Nature Communications 8, article number: 14085. (10.1038/ncomms14085)
- Martin, A. D.et al. 2017. The effect of carboxylate position on the structure of a metal organic framework derived from cyclotriveratrylene. Crystengcomm 19(4), pp. 603-607. (10.1039/C6CE01965J)
2016
- Easun, T.et al. 2016. Structural and dynamic studies of substrate binding in porous metal-organic frameworks. Chemical Society Reviews 46(1), pp. 239-274. (10.1039/C6CS00603E)
- Henley, A.et al. 2016. Computational evaluation of the impact of incorporated nitrogen and oxygen heteroatoms on the affinity of polyaromatic ligands for carbon dioxide and methane in metal-organic frameworks. Journal of Physical Chemistry C 120(48), pp. 27342-27348. (10.1021/acs.jpcc.6b08767)
- Savage, M.et al. 2016. Selective adsorption of sulfur dioxide in a robust metal-organic framework material. Advanced Materials 28(39), pp. 8705-8711. (10.1002/adma.201602338)
- Benson, O.et al. 2016. Amides do not always work: observation of guest binding in an amide-functionalised porous host. Journal of the American Chemical Society 138(45), pp. 14828-14831. (10.1021/jacs.6b08059)
- Pili, S.et al. 2016. Proton conduction in a phosphonate-based metal-organic framework mediated by intrinsic "free diffusion inside a sphere". Journal of the American Chemical Society 138(20), pp. 6352-6355. (10.1021/jacs.6b02194)
- O'Connor, A. E.et al. 2016. Aurophilicity under pressure: a combined crystallographic and in-situ spectroscopic study. Chemical Communications- Royal Society of Chemistry 52, pp. 6769-6772. (10.1039/C6CC00923A)
- Laybourn, A.et al. 2016. Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies. Physical Chemistry Chemical Physics 18(7), pp. 5419-5431. (10.1039/C5CP05426E)
- Krap, C. P.et al. 2016. Enhancement of CO2 adsorption and catalytic properties by Fe-doping of [Ga2(OH)2(L)] (H4L = Biphenyl-3,3′,5,5′-tetracarboxylic Acid), MFM-300(Ga2). Inorganic Chemistry -American Chemical Society- 55(3), pp. 1076-1088. (10.1021/acs.inorgchem.5b02108)
2015
- Jones, C. L., Tansell, A. and Easun, T. 2015. The lighter side of MOFs: structurally photoresponsive metal-organic frameworks. Journal of Materials Chemistry A 4(18), pp. 6714-6723. (10.1039/C5TA09424K)
- Martin, A. D.et al. 2015. Hirshfeld surface investigation of structure-directing interactions within dipicolinic acid derivatives. Crystal Growth and Design 15(4), pp. 1697-1706. (10.1021/cg5016934)
2014
- Xiao, B.et al. 2014. Porous macromolecular dihydropyridyl frameworks exhibiting catalytic and halochromic activity. Journal of Materials Chemistry A 2(46), pp. 19889-19896. (10.1039/c4ta02521k)
- Fiorani, G.et al. 2014. Luminescent dansyl-based ionic liquids from amino acids and methylcarbonate onium salt precursors: synthesis and photobehaviour. Green Chemistry 17(1), pp. 538-550. (10.1039/C4GC01198H)
- Alsmail, N. H.et al. 2014. Analysis of high and selective uptake of CO2 in an oxamide-containing {Cu-2(OOCR)(4)}-based metal-organic framework. Chemistry - a European Journal 20(24), pp. 7317-7324. (10.1002/chem.201304005)
- Warren, M. R.et al. 2014. Solid-state interconversions: Unique 100% reversible transformations between the ground and metastable states in single-crystals of a series of nickel( II) nitro complexes. Chemistry - A European Journal 20(18), pp. 5468-5477. (10.1002/chem.201302053)
- Easun, T.et al. 2014. Photochemistry in a 3D metal-organic framework (MOF): Monitoring intermediates and reactivity of the fac-to-mer photoisomerization of Re(diimine)(CO)(3)Cl incorporated in a MOF. Inorganic Chemistry 53(5), pp. 2606-2612. (10.1021/ic402955e)
- Easun, T.et al. 2014. Modification of coordination networks through a photoinduced charge transfer process. Chemical Science 5(2), pp. 539-544. (10.1039/C3SC52745J)
- Llewellyn, B. A.et al. 2014. Photophysics and electrochemistry of a platinum-acetylide disubstituted perylenediimide. Dalton Transactions 43(1), pp. 85-94. (10.1039/c3dt50874a)
2013
- Tromp, M.et al. 2013. Energy dispersive XAFS: Characterization of electronically excited states of copper(I) complexes. Journal of Physical Chemistry B 117(24), pp. 7381-7387. (10.1021/jp4020355)
2012
- Ke, J.et al. 2012. Electrodeposition of germanium from supercritical fluids. Physical Chemistry Chemical Physics -Cambridge- Royal Society of Chemistry 14(4), pp. 1517-1528. (10.1039/c1cp22555c)
- Brayshaw, S. K.et al. 2012. Photocrystallographic identification of metastable nitrito linkage isomers in a series of nickel(II) complexes. Dalton Transactions 41(1), pp. 90-97. (10.1039/c1dt11379h)
- Wragg, A. B.et al. 2012. Solvent-dependent modulation of metal-metal electronic interactions in a dinuclear cyanoruthenate complex: a detailed electrochemical, spectroscopic and computational study. Dalton Transactions 41(34), pp. 10354-10371. (10.1039/c2dt31001e)
2011
- Cao, Q.et al. 2011. Excited state dependent electron transfer of a rhenium-dipyridophenazine complex intercalated between the base pairs of DNA: a time-resolved UV-visible and IR absorption investigation into the photophysics of fac-[Re(CO)(3)(F(2)dppz)(py)](+) bound to either [poly(dA-dT)](2) or [poly(dG-dC)](2). Photochemical & Photobiological Sciences 10(8), pp. 1355-1364. (10.1039/C1PP05050H)
2010
- Blake, A. J.et al. 2010. Photoreactivity examined through incorporation in metal-organic frameworks. Nature Chemistry 2(8), pp. 688-694. (10.1038/nchem.681)
2009
- Easun, T.et al. 2009. Luminescence and time-resolved infrared study of dyads containing (Diimine)Ru(4,4 '-diethylamido-2,2 '-bipyridine)(2) and (Diimine)Ru(CN)(4) moieties: solvent-induced reversal of the direction of photoinduced energy-transfer. Inorganic Chemistry 48(18), pp. 8759-8770. (10.1021/ic900924w)
- Warren, M. R.et al. 2009. Reversible 100% linkage isomerization in a single-crystal to single-crystal transformation: Photocrystallographic identification of the metastable [Ni(dppe)(eta(1)-ONO)Cl] isomer. Angewandte Chemie - International Edition 48(31), pp. 5711-5714. (10.1002/anie.200901706)
2008
- Easun, T.et al. 2008. Photoinduced energy transfer in a conformationally flexible Re(I)/Ru(II) dyad probed by time-resolved infrared spectroscopy: Effects of conformation and spatial localization of excited states. Inorganic Chemistry 47(12), pp. 5071-5078. (10.1021/ic702005w)
2007
- Herrera, J.et al. 2007. Photophysical and Structural Properties of Cyanoruthenate Complexes of Hexaazatriphenylene. Journal of the American Chemical Society 129(37), pp. 11491-11504. (10.1021/ja072672w)
- Alsindi, W. Z.et al. 2007. Probing the excited states of d(6) metal complexes containing the 2,2 '-bipyrimidine ligand using time-resolved infrared spectroscopy. 1. Mononuclear and homodinuclear systems. Inorganic Chemistry 46(9), pp. 3696-3704. (10.1021/ic0623112)
- Lazarides, T.et al. 2007. Structural and photophysical properties of adducts of [Ru(bipy)(CN)(4)](2-) with different metal cations: Metallochromism and its use in switching photoinduced energy transfer. Journal of the American Chemical Society 129(13), pp. 4014-4027. (10.1021/ja068436n)
2006
- Newell, M.et al. 2006. Structure and properties of dinuclear [Ru-II([n]aneS(4))] complexes of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine. Inorganic Chemistry 45(2), pp. 821-827. (10.1021/ic051151b)
- Shan, N.et al. 2006. Kinetically locked, trinuclear Ru-II metallo-macrocycles - synthesis, electrochemical, and optical properties. Dalton Transactions(23), pp. 2900-2906. (10.1039/B516080B)
- Adams, H.et al. 2006. New members of the [Ru(diimine)(CN)(4)](2-) family: structural, electrochemical and photophysical properties. Dalton Transactions(1), pp. 39-50. (10.1039/B509042C)
2005
- Shavaleev, N. M.et al. 2005. Complexes of substituted derivatives of 2-(2-pyridyl)benzimidazole with Re(I), Ru(II) and Pt(II): structures, redox and luminescence properties (January, pg 3678, 2004) [Correction]. Dalton Transactions(3), pp. 617-617. (10.1039/B500459B)
2004
- Shavaleev, N. M.et al. 2004. Complexes of substituted derivatives of 2-(2-pyridyl)benzimidazole with Re(I), Ru(II) and Pt(II): structures, redox and luminescence properties. Dalton Transactions 21, pp. 3678-3688. (10.1039/B411341A)
2003
- Albrow, V.et al. 2003. Synthesis of an octahydro-1,1 '-binaphthyl thioether ligand and comparison with unhydrogenated binaphthyl analogues. Tetrahedron: Asymmetry 14(18), pp. 2813-2819. (10.1016/S0957-4166(03)00583-4)
The ultimate goal of my work is to combine nanofluidics and metal-organic frameworks (MOFs) with photogated control of molecular flow to create a new platform technology for the development of nanofluidic devices.
A key obstacle in the field of nanofluidics is the lack of well-defined nanostructured materials to study. This has major implications in nanofluidic device design and in our fundamental understanding of molecular behaviour in nanoscale confined spaces.
MOFs are porous crystalline frameworks with applications in the adsorption and separation of a wide range of guest species. Particular interest has developed in the last decade in their potential to store and separate commercially important gases, such as H2, CO2 and CH4. Two key challenges in the field are (i) understanding guest diffusion and (ii) characterising defects in single crystals, both essential to develop MOFs for their primary applications as rapid-response guest storage media.
Our research exploits MOFs to serve three purposes: (a) enabling nanofluidic simulation and experiment to be matched up to enhance fundamental understanding of nano-confined fluid behaviour that can be applied to device design; (b) affording a detailed understanding of the defects in MOFs that impacts their commercial applicability; and (c) opening up new uses for MOFs beyond the traditional and well-studied areas of gas storage and separations.
The challenges of characterising guest diffusion in MOF materials and providing nanoscale ordered architectures for nanofluidic devices are addressed by a two-pronged approach: (i) surface coating of MOFs with photoresponsive molecules to act as gates to the pores, controlling ingress and egress of guests, and (ii) incorporating photoresponsive linkers in MOFs that enable spatio-temporally controlled crystal structure change on photoirradiation. The flow of guests through these materials can be monitored using light microscopies and controlled using laser-induced structural change to block/unblock the MOF pores, ultimately with 3D spatial resolution.
