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Title: Zinc(II) complexes with internal hydrogen bonding interactions : towards more efficient synthetic nucleases
Author: de Rosales, R. T. M.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2005
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A series of zinc(II) complexes of tripodal ligands resembling the catalytic zinc sites of nucleases have been synthesised and fully characterised. Some of these complexes were used to explore strategies to induce the hydrogen bond interactions that influence the catalytic performance of nucleases, and to investigate the factors that affect their strength. X-ray diffraction, NMR and IR studies revealed the formation of hydrogen bonding interactions between amide/amine groups and other zinc-bound ligands both in solution and in the solid state. We have been able to estimate the energies of these hydrogen bonds by IR and VT 1H NMR coalescence studies. From this work, it appears that metal-ligand bonding may be as important as the nature of the hydrogen bond donors and acceptors towards defining the geometry and strength of the hydrogen bond formed. We have investigated the effect of different hydrogen bonding microenvironments on structural features of trigonal bipyramidal [(L)Zn(Cl)]+ cations. Among the implications of introducing hydrogen bonding groups is the lengthening of the axial Zn-Cl and equatorial L-Zn bonds. This structural study may facilitate future structure-function relationships. We have also investigated the effect of these hydrogen bonding microenvironments in the acidity of a zinc(II)-bound water molecule, which is a key parameter of catalytic zinc sites. Thus, from potentiometric titrations it appears that amino hydrogen bonding groups adjacent to a zinc(II)-bound water molecule enhances its acidity as much as 1 pKa unit per hydrogen bonding group. The results presented in this work provide important insights into the possible role(s) of the active site microenvironment in modulating the zinc(II)-promoted hydrolysis of nucleic acids and may contribute to the development of more efficient synthetic nucleases.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available