Research

Part II Projects 2017 (Oxford only)

Prospective Part II students are encouraged to get in touch by email to discuss potential research projects, undertaken within the Goodwin research group. Typical themes may include one or a mixture of the following:

  • Synthesis of functional coordination polymers and metal-organic frameworks
  • Piezoelectric, battery and sensing applications
  • Structural characterization by advanced X-ray diffraction
  • Investigation of phase behaviour and formation of solids
  • In-situ X-ray diffraction studies of crystallization

Opportunities are also available for collaborative projects with groups in NIMS, Japan and Cambridge University.


Summer Projects

Applications are open for undergraduate students in Chemistry to undertake a short (6-8 week) project during the summer vacation 2017, with contribution towards laboratory class marks. Interested students should get in touch by email as soon as possible to discuss potential projects.


Research Interests

My main research interests revolve around the design and synthesis of coordination polymer (CP) materials, and the in-depth characterization of their structures and physical properties. In the future, CPs could potentially be used in several technologies, like catalysts, sensors, magnets and batteries. My goal is to develop greater understanding of them and their functions in devices, both in order to improve performance and to enable the development of materials for new applications.

Coordination polymers

CPs – also known as Metal-Organic Frameworks and Inorganic-Organic Frameworks – are a new class of material with great potential for tailoring to suit many different applications. They are Chemistry’s equivalent of Tinker Toy®: assembly from different molecular building blocks into robust, atomically-precise functional materials has led to the discovery of CPs boasting a diverse range of physical properties, including microporosity, magnetism, luminescence and ionic conductivity. The fascinating thing about coordination polymers, compared with purely organic or inorganic materials, is that the synergy between “organic” and “inorganic” components results in new properties and interesting behaviour, such as flexibility, microporosity and host-guest interactions.

Prototypical porous CP Lithium terephthalate, containing layers of lithium atoms connected by terephthalic acid linkers.Multiferroic CP A CP with exotic mechanical properties, Chiral CP lithium l-tartrate (polymorph 2), containing chains of Li atoms linked by tartaric acid molecules

Formation

Knowledge of the factors affecting the formation of new compounds is critical to obtaining pure, homogeneous and high yield products. CPs are typically synthesized simply by mixing different metal and organic precursors together in a solvent at elevated temperature, without much understanding or control of the chemical processes involved. I am interested in uncovering the underlying thermodynamic and kinetic factors involved in CP formation, in order to improve the synthesis of existing and new materials.

“In Situ Observation of Successive Crystallizations and Metastable Intermediates in the Formation of Metal–Organic Frameworks”
H. H.-M. Yeung, Y. Wu, S. Henke,  A. K. Cheetham, D. O’Hare, R. I. Walton
Angewandte Chemie, International Edition 2016, 55, 2012-2016. DOI: 10.1002/anie.201508763.

“Phase Selection during the Crystallization of Metal-Organic Frameworks; Thermodynamic and Kinetic Factors in the Lithium Tartrate System”
H. H-M. Yeung, A. K. Cheetham
Dalton Transactions 2014, 43, 95-102. DOI: 10.1039/c3dt52430b.

Properties

The structure of crystalline materials, including the majority of CPs, can be determined with atomic precision by X-ray diffraction. I use state-of-the-art single crystal and powder diffraction techniques to perform in-depth characterisation of CP structures, in order to rationalise their physical properties. This information is complemented by collaborators working with several other techniques, including NMR spectroscopy and theoretical calculations, to provide a detailed insight into the behaviour of CP materials.

“Hidden negative linear compressibility in lithium L-tartrate”
H. H.-M. Yeung, R. Kilmurray, C. L. Hobday, S. C. McKellar, Anthony K. Cheetham, D. R. Allan and  S. A. Moggach
Phys. Chem. Chem. Phys. 201719, 3544-3549. DOI: 10.1039/C6CP08690J.

“Topotactic Elimination of Water across a C–C Ligand Bond in a Dense 3-D Metal–Organic Framework”
H. H.-M. Yeung, M. Kosa, J. M. Griffin, C. P. Grey, D. T. Major, A. K. Cheetham
Chemical Communications 2014, 50, 13292-13295. DOI 10.1039/c4cc06136e.

“Chiral, Racemic and Meso- Lithium Tartrate Framework Polymorphs: A Detailed Structural Analysis”
H. H.-M. Yeung, M. Kosa, M. Parrinello, A. K. Cheetham
Crystal Growth and Design 2013, 13 (8), 3705–3715. DOI: 10.1021/cg400741b.

Structure manipulation

In order to fully exploit the synergic capabilities of CPs, fine control over the composition and distribution of the components is critical. One way to achieve this is by mixing different building blocks together in the same structure, known in solid state chemistry as a solid solution. This directly affects the crystal structure and chemical bonding holding it together, and therefore could be used to tune many physical properties. Another way is to create layered materials – nanosheets – that can be peeled apart before restacking in different combinations, enabling multiple functions to be combined in a single material.

“Ligand-Directed Control over Crystal Structure and Solid Solution Formation in Inorganic-Organic Frameworks”
H. H.-M. Yeung, W. Li, P. J. Saines, T. K. J. Köster, C. P. Grey, A. K. Cheetham
Angewandte Chemie, International Edition 2013, 21, 5544-5547. DOI: 10.1002/anie.201300440.

“Isomer-Directed Structural Diversity and its Effect on the Nanosheet Exfoliation and Magnetic Properties of 2,3-Dimethylsuccinate Hybrid Frameworks”
P. J. Saines, M. Steinmann, J.-C. Tan, H. H.-M. Yeung, W. Li, P. T. Barton, A. K. Cheetham
Inorganic Chemistry 2012, 51, 11198-11209. DOI: 10.1021/ic302011x.

Design of new materials

Equipped with an ever-improving understanding of CP structures and their formation, we can now begin to design functional materials for specific applications by assembling certain molecular units into specific structural architectures and incorporating them in devices. In particular, I am interested in the development of novel CPs for applications in future energy storage technology, information technology and sensors…

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