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Research Officer, Materials Structure and Function
NRC Steacie Institute for Molecular Sciences
100 Sussex Drive
Building Sussex,
Room 111
Ottawa, Ontario K1A 0R6
Phone: 613-993-2011, Fax: 613-998-7833
Email: John.Ripmeester@nrc-cnrc.gc.ca
Academic Qualifications B.Sc., Ph.D.
Spoken Languages English
Expertise
Our research is aimed at developing an understanding of weak interactions in the solid state. Such interactions are central to phenomena known collectively as molecular recognition, and are important to a variety of structures and processes in chemistry, physics and biology. The ultimate aim is to be able to design and construct functional solids according to rational design principles, both at the level of the structure of crystals and on a meso-scale, thus leading to nano-structures architectures. Such research also requires the development of a methodology suitable for studying problems of ever-increasing complexity, with crystallography and solid-state NMR spectroscopy as the main techniques in use currently.
We have developed synoptic approaches to study the structure of organic and metal-organic guest-host solids. One class of materials that has been studied thoroughly is the t-butylcalix[4]arenes, where the structure directing and molecular recognition properties of simple guests are well enough understood to consider their use in thin-film or prototypical nanoscale applications. Several novel microporous metal-organic frameworks based on metal coordination compounds have been designed and characterized, some with the promise of having its function as a sorbent switchable in situ.
We have extended the use of xenon NMR spectroscopy as a method to study materials by developing a method for the continuous production of hyperpolarized xenon and integrated this with probe technology in order to allow the recording of NMR spectra and microscopic images with unprecedented sensitivity. Not only does this allow the rapid evaluation of porous materials for the properties of the pore system, but this also allows the time-resolved study of processes such as diffusion, adsorption and desorption.
Gas hydrates are considered to be the best-understood class of guest-host materials, with a wealth of structural and thermodynamic data available, as well as predictive models for their occurrence. Since they occur in both natural and industrial setting and are thought to occur in extraterrestrial space, there is a strong potential for their affecting human welfare (energy source, global climate change, industrial hazard). We have an interest in identifying novel structures, understanding nucleation and crystal growth in such materials for purposes of their control.
Publications and Patents
NRC-authored publication citations are available in the NRC Publications Archive (NPArC); once in NPArC, enter author’s name and select "Author" from the drop-down menu.
Keywords
- Structure
- Dynamics
- Disorder
- Molecular recognition
- Inclusion compounds
- Gas hydrates
- Zeolites
- Molecular sieves
- Hyperpolarized xenon
- NMR Spectroscopy (solid state) and microimaging
- Microporous solids
- Clathrates
- Guest-host materials
- Supramolecular chemistry
