A study of metal-organic frameworks for the storage and release of medical gases
Abstract
This thesis presents a study of the interaction of medical gases nitric oxide, carbon
monoxide and hydrogen sulfide with metal-organic framework materials. Most analysis is
performed via single-crystal X-ray diffraction and Rietveld and pair distribution function
analysis of powder X-ray diffraction data. A background to the field and the
experimental methods used are described in Chapters 1 and 3.
The use of a specially designed static environmental gas cell to assess the role of
coordinatively unsaturated metal sites in nitric oxide storage in Co-CPO-27 via in situ
single-crystal structure determination is described in Chapter 4. Nitric oxide was shown
to bind to the Co-centre of the material in a bent geometry in an approximately 1:1
Co:NO ratio.
A multi-technique study was conducted on the framework Cu-SIP-3 in Chapters
5 and 6, utilising both single-crystal X-ray diffraction and pair distribution function
analysis to obtain complementary information about atomic movements during a
thermally active single-crystal to single-crystal transition. These techniques were further applied during in situ gas-loading experiments on the same framework.
Application of the pair distribution function technique to metal-organic
frameworks is described in Chapter 7, where refinements of both known and unknown
metal-organic framework structures are presented. Partial PDFs are used to determine
the secondary building block of a new metal-organic framework and verify the structural
solution determined from powder X-ray diffraction data.
Chapter 8 presents the study of the M-CPO-27 isostructural series for the
adsorption and release of hydrogen sulfide and carbon monoxide. Gas adsorption
isotherms and release measurements are correlated with the structure of the Ni-CPO-27 hydrogen sulfide-adduct determined by both powder X-ray diffraction and differential pair distribution function methods which reveal the open-metal site as the primary adsorption interaction in the material. The hydrogen sulfide released from Zn-CPO-27 is
determined to be biologically active through vasodilatation experiments.
Type
Thesis, PhD Doctor of Philosophy
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