Abstract
This thesis presents the results of a study of the collective properties of hydrogen bonded adducts, in order to determine how changes in the hydrogen bonding environment afffect each hydrogen bond. The focus is on non-additive properties, particularly anti-cooperativity, instances where the over-all interactions amount to less than the sum of the individual effects. The emphasis of the investigation is on the IR red-shifts induced by hydrogen bonds, and these are presented in redshift plots. A comprehensive overview is obtained of the extent of anti-cooperativity exhibited by the adducts of protonated water, protonated alcohols, protonated formic acid, and 11 hydrogen-bond acceptors.
The inuence on anti-cooperativity of both the hydrogen-bond donor and acceptor is investigated, and we find that the strength of the individual hydrogen bond determines the over-all degree of anti-cooperativity, when considering the same donor. The stronger hydrogen bonds are more affected by other hydrogen bonds to the same donor, and at the same time, the stronger hydrogen bonds affect other hydrogen bonds more. These conclusions are based on the results of computational studies as well as on experimental results derived from infrared Ar-predissociation spectra.
Furthermore, anti-cooperativity is observed for donors, where the donating OH-groups are separate by up to 5 CH-groups. Both saturated and unsaturated donors exhibit anti-cooperativity, although the effect is largest for the unsaturated donors. We find that both cooperativity and anti-cooperativity can be understood by considering proton affnities of adducts and proton affnity differences.
The inuence on anti-cooperativity of both the hydrogen-bond donor and acceptor is investigated, and we find that the strength of the individual hydrogen bond determines the over-all degree of anti-cooperativity, when considering the same donor. The stronger hydrogen bonds are more affected by other hydrogen bonds to the same donor, and at the same time, the stronger hydrogen bonds affect other hydrogen bonds more. These conclusions are based on the results of computational studies as well as on experimental results derived from infrared Ar-predissociation spectra.
Furthermore, anti-cooperativity is observed for donors, where the donating OH-groups are separate by up to 5 CH-groups. Both saturated and unsaturated donors exhibit anti-cooperativity, although the effect is largest for the unsaturated donors. We find that both cooperativity and anti-cooperativity can be understood by considering proton affnities of adducts and proton affnity differences.
| Original language | Danish |
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| Publisher | Department of Chemistry, Faculty of Science, University of Copenhagen |
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| Number of pages | 135 |
| Publication status | Published - 2013 |