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Title: Computational studies towards the expansion of supraicosahedral heteroborane chemistry
Author: McKay, David
ISNI:       0000 0004 2712 1363
Awarding Body: Heriot-Watt University
Current Institution: Heriot-Watt University
Date of Award: 2010
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This thesis describes a series of density functional theory (DFT) studies that investigate the processes underlying the synthesis of supraicosahedral (>12 vertex) heteroboranes. The reduction of carborane isomers, closo-C2B12H12 to [nido-C2B12H12]2-, was modelled, where the results were consistent with experiment. The oxidation of [7,9-R27,9-nido-C2B12H10]2- was found to be dependent on R, where the reducing potential (ΔEOX) was 4.8 kcal mol-1 for R = H. Electron withdrawing p-C6F4CF3 groups (ΔEOX = 60.8 kcal mol-1) were suggested as synthetic targets. The structural chemistry of 12- and 13-vertex stannacarboranes and related platinacarboranes was investigated. The degree of slip in these species was found, in general, to be controlled by steric interactions between the metal and carborane fragments. Structural preferences in 12- and 13-vertex heteroboranes, X2Bn-2Hn and Y2Bn-2Hn-2 (X = C, Si, Ge, Sn; Y = P, As, Sb, Bi) were investigated. Phosphaboranes were suggested for polyhedral expansion as they showed the largest number of stable isomers. Observation of C–C cleavage of an arene in a bis(carborane) species was rationalised computationally. The reaction was found to proceed via an internal REDOX pathway, whereby cleavage was invoked by electron transfer from a nido carborane cage to the central arene of a triple-decker intermediate.
Supervisor: Macgregor, Stuart A. ; Welch, Alan J. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available