Computational investigations of the electronic structure of molecular mercury compounds: ion-selective sensors

dc.contributor.authorAfaneh, Akef
dc.contributor.examiningcommitteeBudzelaar, Peter (Chemistry) Whitmore, Mark (Physics and Astronomy) Wang, Feiyue (Environment and Geography) Wetmore, Stacey (Chemistry and Biochemistry, University of Lethbridge)en_US
dc.contributor.supervisorSchreckenbach, Georg (Chemistry)en_US
dc.date.accessioned2015-08-11T17:11:20Z
dc.date.available2015-08-11T17:11:20Z
dc.date.issued2012-03en_US
dc.date.issued2014-06en_US
dc.date.issued2014-07en_US
dc.date.issued2015-06en_US
dc.degree.disciplineChemistryen_US
dc.degree.levelDoctor of Philosophy (Ph.D.)en_US
dc.description.abstractThis thesis presents the basic concepts of electronic structure theory and the chemical properties of mercury. The theoretical foundation of DFT and the consequences of relativity are also introduced. The electronic structure of Hg(II) ions, [Hg(L)n(H2O)m]q (L = HO-, Cl-, HS-, S2-) has been studied. We show, in this thesis, that the charge transfer (that is calculated from the hard-soft-acid-base principle (Pearson’s principle)), the total NBO charge and the interaction energies are strongly correlated. Our studies indicate the effect of the solvent on the global electrophilicity, the charge transfer and consequently the interaction strength between Hg(II) and ligand L. The formation constants, logK, of Hg2+−complexes are calculated. The procedure that we follow in this thesis to calculate the formation constants, logK’s, are in good agreement with the extrapolated experimental values. We introduce and explain why it is important adding water molecules explicitly during the calculations of the logK. The recommended logK value of HgS is 27.2. We examined two different types of organic compounds as sensors for heavy metal ions: lumazine (Lm) and 6-thienyllumazine (TLm). We found that the simple calculation of pKa values using DFT methods and implicit solvent models failed to reproduce the experimental values. However, calculated orbital energies and gas phase acidities both indicate that the compound TLm is inherently more acidic than the parent species Lm. We demonstrate that: (1) we need to take in our consideration the population of each tautomer and conformer during the calculations of the pKa values, and (2) thienyl group has indirect effect on the acidity of the proton on N1 in the uracil ring. Last but not least, the fluorescence spectrum of the sensors (L) and their [(L)nM(H2O)m]2+ complexes (L = Lumazine (Lm) and 6-thienyllumazine (TLm) and M = Cd2+and Hg2+) are calculated using time dependent DFT (TDDFT). The results show that TDDFT is in good agreement with experimental results. This chapter provides a new concept in the design of fluorescence turn-on/off sensors that has wider applicability for other systems. Finally, we provide a summary of the works compiled in this thesis and an outlook on potential future work.en_US
dc.description.noteOctober 2015en_US
dc.identifier.citationHarvarden_US
dc.identifier.citationVancouveren_US
dc.identifier.citationACS Styleen_US
dc.identifier.citationACS Styleen_US
dc.identifier.urihttp://hdl.handle.net/1993/30661
dc.language.isoengen_US
dc.publisherSpringer International Publishing AGen_US
dc.publisherWileyen_US
dc.publisherAmerican Chemical Societyen_US
dc.publisherAmerican Chemical Societyen_US
dc.rightsopen accessen_US
dc.subjectComputational chemistry, Molecular modelling, Density functional theory (DFT), Mercury complexes, Hard-soft acid base principle (HSAB), Formation constant, Metal orbital controlen_US
dc.titleComputational investigations of the electronic structure of molecular mercury compounds: ion-selective sensorsen_US
dc.typedoctoral thesisen_US
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