Anthony William Addison

Structural characteristics are reported for two thioether–ketones, Dtdpe and Mtdp [2-({2-[(2-oxo-2-phenylethyl)sulfanyl]ethyl}sulfanyl)-1-phenylethan-1-one, C₁₈H₁₈O₂S₂, and 2-[(2-oxo-2-phenylethyl)sulfanyl]-1-phenylethan-1-one, C₁₆H₁₄O₂S], and for related derivatives, the bis(pyridylhydrazones) Dhpk and Prpsb [2-((2E)-2-{(2Z)-2-phenyl-2-[2-(pyridin-2-yl)hydrazin-1-ylidene]ethylidene}hydrazin-1-yl)pyridine, C₁₈H₁₆N₆, and 2-[(2Z,12Z)-3,12-diphenyl-14-(pyridin-2-yl)-5,10-dithia-1,2,13,14-tetraazatetradeca-2,12-dien-1-yl]pyridine, C₃₀H₃₂N₆S₂], as well as for the macrocyclic thiocarbohydrazide derivative Ctrsp [(3E,8Z)-3,9-dimethyl-1,11-dithia-4,5,7,8-tetraazacyclotetradeca-3,8-diene-6-thione, C₁₀H₁₈N₄S₃]. Three of the five compounds exhibit conformational enantiomerism in the solid state. The occurrence of intra- and intermolecular hydrogen bonding is commented upon through quantum mechanical (DFT) calculations. Weak C—H...S interactions are noted, while stronger N—H...N and N—H...S hydrogen bridges are delineated.

Reactions between 15-metallacrown-5 {GdCu₅}³⁺ and [Cr(C₂O₄)₃]³⁻ or [Cu(C₂O₄)₂]²⁻ resulted in the formation of two 1D coordination polymers, which are the first examples of 15-metallacrowns-5 possessing a magnetocaloric effect.

Fossil fuels are a finite resource and will eventually run out. The use of fossil fuels contributes to global warming from air pollution created mainly by the greenhouse gas carbon dioxide, which encourages using other energy alternatives. Finding clean and renewable energy sources such as wind power, hydropower and photovoltaics is one of the top priorities in science. Solar energy is one of the main renewable sources being invested in, it is clean and abundant and can benefit the world. There are different types of photovoltaic cells, solar cells, such as silicon cells, thin-film cells, polymer cells, organic cell, perovskite cells, quantum dot and dye-sensitized solar cells (DSSCs) that have been widely investigated due to their high potential for solving the energy problem. DSSCs are investigated in this thesis. In this work, different classes of compounds were investigated, based on bzimpy, pyrazole, NTB in chapter 2 and dibenzo[b,j][1,10]phenanthrolines in chapter 3 which highlight the effect of having multiple groups on the dye molecule as well as the extended aromaticity, on the properties of ruthenium-based DSSCs. For bzimpy, pyrazole and NTB, first, novel ligands were designed, synthesized, and then N-alkylation method was utilized which works systematically unlike some previous methods in the literature, to insert different groups on the ligand. Dyes were synthesized using the ligands: mebzimpy, prbzimpy, npbzimpy and anbzimpy had power conversion efficiencies ([eta]) of 0.38%, 11.58%, 0.34% and 0.28% respectively. For pyrazole derivatives, Dyes were synthesized form quinolyldiphenylpyrazole and quinolyldi-t-butylpyrazole ligands had power conversion efficiencies ([eta]) of 2.14% and 0.81%, respectively. NTB-based dyes synthesized from Et₃NTB, Pr₃NTB and Np₃NTB had power conversion efficiencies ([eta]) of 0.20%, 0.28% and 0.13% respectively. For dibenzo[b,j][1,10]phenanthrolines, a synthetic scheme was developed that improves previously used methods, creating the possibility of making a library of novel compounds to be used for future investigations. These ligands were then coordinated to ruthenium, and finally ruthenium complexes (dyes) were studied and evaluated for their application in DSSCs. Phenanthroline dyes synthesized form dsdhphen, dsphen, badhphen and baphen had power conversion efficiencies ([eta]) of 0.35%, 0.46%, 0.59% and 0.52% respectively. It was found that all these dyes display extended absorption of 622 to 628 nm in comparison to the reference dye (N719) which is 533 nm. Pyrazole-based dyes had the highest overall efficiency among investigated groups. However, increasing the absorption maxima to longer wavelengths does not necessarily increase the efficiency.

Syntheses are described for the blue/purple complexes of cobalt(II) chloride with the tetradentate ligands 1,4-bis[2-(pyridin-2-yl)ethyl]piperazine (Ppz), 1,4-bis[2-(pyridin-2-yl)ethyl]homopiperazine (Phpz), trans-2,5-dimethyl-1,4-bis[2-(pyridin-2-yl)ethyl]piperazine (Pdmpz) and tridentate 4-methyl-1-[2-(pyridin-2-yl)ethyl]homopiperazine (Pmhpz). The CoCl₂ complexes with Ppz, namely, {μ-1,4-bis[2-(pyridin-2-yl)ethyl]piperazine}bis[dichloridocobalt(II)], [Co₂Cl₄(C₁₈H₂₄N₄)] or Co₂(Ppz)Cl₄, and Pdmpz (structure not reported as X-ray quality crystals were not obtained), are shown to be dinuclear, with the ligands bridging the two tetrahedrally coordinated CoCl₂ units. Co₂(Ppz)Cl₄ and {dichlorido{4-methyl-1-[2-(pyridin-2-yl)ethyl]-1,4-diazacycloheptane}cobalt(II) [CoCl₂(C₁₃H₂₁N₃)] or Co(Pmhpz)Cl₂, crystallize in the monoclinic space group P2₁/n, while crystals of the pentacoordinate monochloro chelate 1,4-bis[2-(pyridin-2-yl)ethyl]piperazine}chloridocobalt(II) perchlorate, [CoCl(C₁₈H₂₄N₄)]ClO₄ or [Co(Ppz)Cl]ClO₄, are also monoclinic (P2₁). The complex {1,4-bis[2-(pyridin-2-yl)ethyl]-1,4-diazacycloheptane}dichloridocobalt(II) [CoCl₂(C₁₉H₂₆N₄)] or Co(Phpz)Cl₂ (P\overline{1}) is mononuclear, with a pentacoordinated Co^II ion, and entails a Phpz ligand acting in a tridentate fashion, with one of the pyridyl moieties dangling and non-coordinated; its displacement by Cl⁻ is attributed to the solvophobicity of Cl⁻ toward MeOH. The pentacoordinate Co atoms in Co(Phpz)Cl₂, [Co(Ppz)Cl]⁺ and Co(Pmhpz)Cl₂ have substantial trigonal–bipyramidal character in their stereochemistry. Visible- and near-infrared-region electronic spectra are used to differentiate the two types of coordination spheres. TDDFT calculations suggest that the visible/NIR region transitions contain contributions from MLCT and LMCT character, as well as their expected d–d nature. For Co(Pmhpz)Cl₂ and Co(Phpz)Cl₂, variable-temperature magnetic susceptibility data were obtained, and the observed decreases in moment with decreasing temperature were modelled with a zero-field-splitting approach, the D values being +28 and +39 cm⁻¹, respectively, with the S = 1/2 state at lower energy.

Several copper and nickel complexes of thioether ether ligands with heterocyclic aromatic ligands have been prepared. The metal complexes have been characterized by diverse physical techniques. Crystal structures of the metal complexes display various geometries and coordination numbers. The crystal structures of two ligands were also determined. The majority of the ligands synthesized contain heterocyclic nitrogen donor groups besides thioether sulfurs. The copper complexes of thioether donor ligands show high redox potentials. The donor atom arrangement leads to relatively strong optical absorption in the uv-visible spectra of the copper complexes. By carefully altering the ligand design a wide variety of Ni(II) complexes with geometries varying from diamagnetic square planar to paramagnetic octahedral were prepared. Some of these complexes support Ni(I) as evidenced by electrochemistry.

The title compound, [Eu(C₉H₁₀BN₆)(C₁₉H₁₅O₂)₂(C₃H₇NO)] or [TpEu(Anthracac)₂(DMF)], was synthesized by reaction of a tris(pyrazolyl)borate (Tp⁻) Eu³⁺ complex with 3-(anthracen-9-yl)pentane-2,4-dione (HAnthracac) in the presence of triethylamine. In the title compound, Eu³⁺ is located in an octavertex square-pyramidal coordination environment. In the two Anthracac⁻ ligands, the anthracene and nearly planar acetylacetonate fragments are almost orthogonal. Neighboring molecules of TpEu(Anthracac)₂(DMF) are connected in the crystal by intermolecular van der Waals interactions, while π-stacking interactions are limited to the edges of two anthracene rings.