Browsing by Author "Greyling, Barend Petrus"
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- ItemA DFT study concerning Van der Waals driven Self /Hetero-association reactions of [PtII(1,10-Phenanthroline)(N-pyrrolidyl-N-(2,2- dimethyl-propanoyl)thiourea)]+ and Fluoranthene(Stellenbosch : Stellenbosch University, 2019-12) Greyling, Barend Petrus; Gerber, Wilhelmus Jacobus; Dillen, JanENGLISH ABSTRACT: The self-association of Fluoranthene (reaction 1), hetero-association of [PtII(1,10-Phenanthroline)(N -pyrrolidyl-N-(2,2-dimethyl-propanoyl)thiourea)]+ and Fluoranthene (reaction 2), and the self-association of [PtII(1,10-Phenanthroline)(N -pyrrolidyl-N-(2,2-dimethylpropanoyl) thiourea)]+ (reaction 3) were computationally investigated via Density Func tional Theory. Due to the non-covalent character of all three reactions two strategies where implemented to in an attempt to identify conformational preference prior to geometry optimisation. Firstly, the inter-molecular potential energy surface for reaction 1 and 2 were generated. From these potential energy surfaces six Fluoranthene dimers and three [PtII(1,10-Phenanthroline)(N -pyrrolidyl-N-(2,2-dimethyl-propanoyl)thiourea)]+ · · · Fluoranthene adducts were found. Due to the presence of non-planar aliphatic moieties connected to the thiourea ligand, no inter-molecular potential energy surface could be generated for reaction 3. Rather, a novel Inter Fragment Nearest Neighbour technique was developed, which was found to produce good initial pre-optimised geometry estimates for all three reactions. Dispersion was found to be the dominant stabilising nett interaction energy contribution in all three reactions. The electrostatic interaction energy contribution was found to be stabilising in reactions 1 and 2, and destabilising in reaction 3. The self-association reaction of [PtII(1,10-Phenanthroline)(N -pyrrolidyl-N-(2,2-dimethyl-propanoyl)thiourea)]+ was found to be highly dependent on solvation. The calculated standard for reaction 2 (∆Go R = -0.65±0.53) and reaction 3 (∆Go R = -2.01±1.99) were found to fall within two standard deviations of experimental values, whereas reaction 1 (∆Go R = 5.20±0.95) assumed a value beyond two standard deviations. The sign of the standard reaction Gibbs energies in all three reactions were however in correspondence with experimental values.