| Popis: |
The original reports of metal complexes of N-heterocyclic carbenes (NHCs) by Öfele and Wanzlick, the continuing investigations by Lappert, and the isolation of free carbenes by Arduengo provided the foundation to a growing area of chemistry. A recent advance in the area is the use of silver NHC complexes as carbene transfer reagents. The use of silver NHCs as transfer reagents has allowed for the exploration of other less accessible metal NHC systems. To date, metal NHC complexes have primarily been synthesized and used for catalytic functions; however, N-heterocyclic carbenes have begun to be investigated for medicinal use by our group, as well as others. This dissertation discusses the syntheses of imidazolium salts, which are precursors to N-heterocyclic carbenes, as well as the syntheses of a variety of silver NHC complexes. Chapter 1, the introduction, gives an overview of silver NHC chemistry and reports the current syntheses, properties and application of silver NHCs. Chapter 2 focuses on the synthesis and characterization of an imidazolium linked cyclophane and the synthesis of the corresponding silver NHC complex. Chapters 3 and 4 involve the isolation of cationic tetranuclear silver clusters that are stabilized by N-heterocyclic carbenes that have been incorporated into macrocyclic ligands. These complexes are the first examples of N-heterocyclic carbenes bridging two metals. Chapter 5 focuses on the syntheses of imidazolium linked cyclophanes that incorporate other donor groups into the macrocyclic ligands. Also, reported is the synthesis of a cyclophane that has an expanded cavity size that could accommodate larger metals. Also, discussed in Chapter 3 is the beginning of our investigation of silver N-heterocyclic carbenes as potentially useful medicinal reagents. The synthesis of silver NHCs from water is ideal for their application for medicinal use. In chapter 6, we explored the use of silver NHCs in the synthesis of a radiopharmaceutical. The design and characterization of two imidazolium salts, that could be easily attached to a targeting moiety is reported. Also, discussed is the exploration of the silver chemistry of these two NHC precursors. |
