Au I Complexes

Olefin and acetylene complexes of Au(I) can be prepared by direct iateraction of the unsaturated compounds with a Au(I) hahde (190,191). The resulting products, however, are not very stable and decompose at low temperatures. Reaction with Au(III) hahdes leads to halogenation of the unsaturated compound and formation of Au(I) complexes or polynuclear complexes with gold ia mixed oxidatioa states. 

Sodium borohydride reductions of gold(I) complexes give Au clusters at RT if sodium borohydride in ethanol is dropped slowly into a suspension of the Au(I) complex in the same solvent. The immediate coloring of the reaction mixture (mostly red), even after only a few drops of the borohydride have been added, indicates fast formation of Au clusters. In view of the complicated composition of these compounds the fast formation is surprising. The use of H2 and CO with HjO as reducing agents in the synthesis of gold clusters has been described (see Table 1, Method A, 8.2.2.2). 

Table 1.2 gives the Au Au distances, and Au Au Au and N-Au-N angles for several homobridged tetranuclear Au(I) complexes and tetranuclear gold amidi-nate complexes. Similar structural arrangements have been found in the tetrameric l,3-diphenyltriazenidogold(I) complex, [Au(PhNNNPh)]4 (Au Au = 2.85 A) [21],... 

This Au(I) complex was tested as co-catalyst in palladium-catalyzed alkynylation reactions but this derivative is much less active than the analogous chloride complex [AuCl(tht)] needing over twice as long to fully convert the starting material [42]. 

When the Au(I) complex [Au(CGF5)(tht)j reacts with lithium l-methylimidazol-2-yls the organic compound is protonated or alkylated and the carbene complexes are obtained [67] (see Figure 3.3). 

The structure of the complex [Au(pdma)2][Au(C6F5)2] was studied by X-ray crystallography and was the first full X-ray analysis of a four-coordinate Au(I) complex and also the first of an [AUR2] anion where R is an organic group. 

Pan, Q.-J. and Zhang, H.-X. (2003) Aurophilic attraction and excited-state properties of binuclear Au(I) complexes with bridging phosphine and/or thiolate ligands An ah initio study. Journal of Chemical Physics, 119, 4346-4352. 

Besides intermolecular Au Au interactions, visible metal-centered emission of mononuclear Au(I) complexes is usually associated with trigonal, non-centro-symmetric coordination at Au(I). For example, mononuclear two-coordinate bis... 

Omary M.A., Mohamed, A.A., Rawashdeh-Omary, M.A. and Fackler, J.P. Jr (2005) Photophysics of supramolecular binary stacks consisting of electron-rich trinuclear Au(I) complexes and organic electrophiles. Coordination Chemistry Reviews, 249, 1372-1381. 

Fackler, J.J., Grant, T.A., Hanson, B.E.and Staples, R.J. (1999) Characterisation of luminescent, homoleptic, three coordinate, water soluble Au(I) complex of trisulfonated triphenylphosphine (TPPTS) as the caesium salt, Cs8[Au(TPPTS)j]. 5.25H2O. Cold Bulletin, 31, 20-23. 

Comparing an Au(I) complex with an Au(III) complex with the same ligands, the isomer shift of the latter is more positive and its quadrupole splitting is smaller. 

The cytotoxicity of Au(I) complexes is markedly dependent on the ligands. A large number of Au(I) phosphine complexes are toxic to cells in the micromolar concentration range. For example, some linear Au(I) phosphine complexes, including the antiarthritic complex aura-nofin (see Section VII), are potently cytotoxic toward cancer cells in culture (189). 

Au((J.-mesityl)]5 (mesityl = 2,4,6-Me3C6H2) as precursor. This Au(I) complex is dissolved first in OA and injected into a heated (300 °C) solution of HDA leading to nanoparticles ranging in size from 10 to 80 nm. Nevertheless, when a more diluted solution of complex [Au( t-mesityl)]5 in OA is injected into a TOPO solution at 190 °C, highly monodisperse gold nanoparticles of 12 lnm are obtained [83] (Scheme 3.11). 

Stradiotto et al. prepared some Au(I) complexes supported by donor-functionalized indene ligands that showed catalytic properties for aldehyde hydrosilylation [185]. 

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