Date of Award

2017

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

Sub-Department

College of Arts and Sciences

First Advisor

Richard D. Adams

Abstract

Chapter 1 presents the most relevant literature in the field of carborane chemistry. The focus is on icosahedral carboranes and the different methods of boron or carbon atoms substitution and functionalization. The direct addition of transition metal to boron atoms is covered in detail as well as strategies for cage opening of icosahedral carboranes.

Chapter 2 reports the preparation of some of the first polynuclear metal carbonyl cluster complexes where the closo-carborane cage: o-C2B10H12 serves as a ligand on the face of one (Os3(CO)93-4,5,9-C2B10H10)(µ-H)2, 2.1) and two triosmium clusters (Os3(CO)9(µ-H)23-4,5,9-µ3-7,11,12-C2B10H7)Os3(CO)9(µ-H)3, 2.3), and the resulting opening of the cage in the presence of two metal clusters to form Os3(CO)9(µ-H)(µ3-3,4,8-µ3-7,11,12-C2B10H6)Os3(CO)9(µ-H), 2.4.

Chapter 3 reports on a further investigation of the reaction of closo-carboranes with trimetallic clusters. The thiolate substituted derivative of o-C2B10H12, closo-o-(1-SCH3)C2B10H11 also reacts with Os3(CO)10(NCMe)2. As with o-C2B10H12, it is possible to add one and two Os3(CO)9 cluster units to the surface of the carborane and in the latter case, the carborane cage is also opened, but more importantly, in this case the opening occurs in a stepwise process that provides new insight into the mechanism of the cage opening process.

Chapter 4 presents the coordination chemistry of thioether-carboranes on dirhenium carbonyl cluster complexes. To follow up on our studies of the reaction and cage opening of closo-o-(1-SCH3)C2B10H11 and o-C2B10H12 on triosmium clusters, we investigated the reaction of closo-o-(1-SCH3)C2B10H11 and closo-[o-1,2-(SCH3)2]C2B10H10 with dirhenium complex Re2(CO)8[μ-η2-C(H)C(H)Bun](μ-H). Two isomers were obtained from the reaction with closo-o-(1-SCH3)C2B10H11, Re2(CO)8[μ-η2-1,3-C2B10H10(1-SCH3)](μ-H), 4.1 and Re2(CO)8[μ-η2-1,4-C2B10H10(1-SCH3)](μ-H) 4.2 and one product Re2(CO)7[μ-η3-C2B10H9(1,2-SCH3)2](μ-H), 4.3 from the reaction with [o-1,2-(SCH3)2]C2B10H10. The synthesis, characterization and reactions are discussed.

Chapter 5 introduces the chemistry furan ligands on transition metal cluster complexes. Furans are products from the processing of biomass and intermediates in the production of biofuels. We have activated multiple C-H bonds of a furan ligand using transition metal clusters and obtained several new sandwich furyl and furyne cluster compounds. Starting with the furyl complex Os3(CO)10(μ,η2-C4H3O) (μ-H), 5.1 and furyne (μ-H)2Os3(CO)932-C4H2O), 5.2 and reacting them with a dirhenium carbonyl cluster complexes, we have obtained two new sandwich structures, (μ-H)Os3(CO)10(μ-η2-2,3,μ-η2-4,5-C4H2O)Re2(CO)8(μ-H), 5.3 and (μ-H)2Os3(CO)932-2,3-,μ-η2-4,5-C4HO)Re2(CO)8(μ-H), 5.4 respectively. Compound 5.2 also reacts with a second triosmium cluster to form a new “Os6” furyne sandwich cluster, (μ-H)2Os3(CO)932-2,3-,μ-η2-4,5-C4HO)Os3(CO)10(μ-H), 5.5. Such sandwich furan structures formed by multiple C-H bond activations by different transition metals have not yet been reported.

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