At the interface of main group and organometallic chemistry: Synthetic, structural, and reactivity studies of metallatricarbadecaboranes

Metallatricarbadecaboranes can be considered analogues of their corresponding metallocenes, but with distinct and complementary properties including enhanced oxidative, thermal and hydrolytic stability. The main goal of research discussed in this dissertation was to develop systematic methods for the functionalization of metallatricarbadecaboranes, 1-(eta5-C 5H5)-2-Ph-closo-1,2,3,4-RuC3B 7H9 (M = Ru, Fe), that would allow the attachment of substituent groups needed for their potential applications in the biomedical or electronic/optical materials fields. The main accomplishments towards this goal were: 1.) A general method for cage-boron functionalization based on cage-boron halogenation followed by Sonogashira couplings was expanded and applied to the ruthenatricarbadecaborane family to yield complexes of the general formula 1-(eta 5-C5H5)-2-Ph-6-R-closo-1,2,3,4-RuC 3B7H9 (R = alkynyl). 2.) New methods for cage-carbon functionalization were achieved based on the synthesis of carbon-iodinated complexes followed by Sonogashira, Heck, and Stille type palladium couplings, to yield 1-(eta5-C5H5)-2-Ph- closo-1,2,3,4-RuC3B7H9 (R = alkenyl, alkynyl). 3.) Click chemistry reactions of alkynyl substituted metallatricarbadecaboranes were applied to develop new routes to cage-carbon substituted metallatricarbadecaboranes 1-(eta5-C 5H5)-2-R-Ph-closo-1,2,3,4-RuC3B 7H9 R = triazole), including amino-acid derivatives. The new functionalized complexes include conjugated complexes, which could be used in the electronic/optical materials field, complexes with biological groups, some of which have shown potential as anticancer agents or BNCT carriers, bimetallic systems, and complexes with active chemical groups that could allow for further functionalization. In other work, the synthesis of the first members of the new families of ten vertex nido- and closo- metallanonacarbaboranes (2-(eta5-C5H5)-10-Ph- closo-2,1,6,10-M-C3B6H8 (M = Ru, Fe) and Bu4N+[5,5,5-(CO)3-10-Ph- nido-5,6,9,10-Re-C3B6H9] -), was accomplished through cage deboronation reactions. Finally, a new method for the synthesis of cyclobutadienylcobalt tricarbadecaborane (1-(eta4-C4(CH3) 4)-2-Ph-closo-1,2,3,4-CoC3B7H9) was achieved, as well as the isolation of cobalt and rhodium carborane mixed-ligand complexes containing the diphenylphosphinoethane ligand (1,1-(Ph2P) 2Et-2-Ph-closo-1,2,3,4-RhC3B7H9). The diverse methods discussed in this dissertation have made the synthesis of metallatricarbadecaboranes with functional groups appropriate for a variety of potential applications easily accessible.