| Chapter 1. The synthesis of water-soluble, boron-substituted carborane derivatives was achieved by treatment of boron-substituted bromoalkyl carborane derivatives with trimethylphosphine to yield the corresponding phosphonium salts. These new carborane salts exhibit solubility in both aqueous and polar organic media. Herein we report the synthesis and characterization of the first water-soluble, boron-substituted carborane species, closo-9,12-(CH 2CH2CH2P(CH3)3+Br −)2-1,2-C2B10H10, 4, and closo-3-[CH2CH2CH 2P(CH3)3+Br−]-1,2-C 2B10H11, 5. The crystal structure of 4 and 5 are reported. Additionally, another method of preparing mono- and difunctionalized water-soluble phosphonium salts of B3-substituted carborane derivatives was developed. This method produces both the monophosphonium salt, closo-3-[CH2CH(CH 2I)CH2P(CH3)3+I −]-1,2-C2B10H11, 8, and the diphosphonium salt, closo-3-[CH2CH(CH 2P(CH3)3+I−) 2]-1,2-C2B10H11, 9.; Chapter 2. Reaction of both closo-9,12-I 2-1,2-C2B10H10 and closo-9,10-I 2-1,7-C2B10H10 with an excess of the appropriate aryl Grignard reagent in the presence of PdCl2(PPh 3)2 gives the corresponding closo-9,12-(4-aryl-C 6H4)2-1,2-C2B10H10 and closo-9,10-(4-aryl-C6H4) 2-1,7-C2B10H10 in good to high yields. The X-ray structures of 1, 3, 6 and 10 established that their carborane C-H vertices are involved in extended networks directed by weak non-classical C-Hπ hydrogen bonding in the solid-state.; Chapter 3. The syntheses of cyclohexamers 8, 9 and X-ray diffraction study of cyclohexamer 6 are reported. These macrocycles, composed of diaryl ortho-carborane derivatives as modular building blocks, represent the largest carboracycles reported to date featuring 30 and 36-membered rings. The centrosymmetric cyclohexamer 6 crystallized in a pseudo chair conformation with eight solvent molecules of 1,3-dimethoxybenzene with two solvent molecules laying above and below the center of the cavity.; Chapter 4. We have described the synthesis of second generation synthons and their use and potential in the formation of tailor made carboracycles, having a range of cavity sizes and varying degrees of flexibility. These synthons, generated from the tethering of diaryl- ortho-carborane derivatives with bifunctional organic linkers, ultimately led to fairly functionalizable carboracycles. The chemistry of these novel carboracycles allowed for the synthesis of the first known water-soluble carboracycle 6 and the syntheses of 10 and 22 with potential use as host for organic compounds and metal ions, respectively. The structures of 6, 10 and 22 have been determined by X-ray crystallography. |
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