New chemistry with gold-nitrogen complexes: synthesis and characterization of tetra-, tri-, and dinuclear gold(I) amidinate complexes. Oxidative-addition to the dinuclear gold(I) amidinate

摘要

Nitrogen ligands have been little studied with gold(I) and almost no chemistryhas been described using anionic bridging nitrogen ligands. This dissertation concernsthe impact of the bridging ligands amidinate, ArNHC(H)NAr, on the chemistry of gold(I)and, in particular, the effect of substituents on the molecular arrangement. The electronicvs. steric effect of the substituents on the molecular arrangement of gold(I) amidinatescomplexes is studied in detail. Tetra-, tri-, and dinuclear gold(I) amidinate complexesare synthesized and characterized using X-ray diffraction. Spectroscopic andelectrochemical studies of the amidinate complexes are described. Catalytic studiessuggest that gold amidinates and related gold nitrogen complexes are the best catalystprecursors for CO oxidation on TiO2 surface reported to date (87% conversion).The dinuclear gold(I) amidinate complex with a Au? ?Au distance of 2.711(3) ? is rare. To our knowledge, there is only one other example of a symmetrical dinucleargold(I) nitrogen complex. Oxidative-addition reactions to the dinuclear gold(I) complex,[Au2(2,6-Me2-form)2] are studied in detail and result in the formation of gold(II) complexes. The gold(II) amidinate complexes are the first formed with nitrogen ligands.The complexes are stable at room temperature.Mixed ligand tetranuclear gold(I) clusters and tetranuclear mixed Au-Ag metalclusters of pyrazolate and amidinate ligands are synthesized and characterized using Xraydiffraction.