Gold complexes structures

The remarkable stability of the gold complexes is due to significant metal-metal bonding. However, their isolation and structural study are remarkable and greatly contributed to our knowledge of higher-coordinate carbocations. 

The soft Au+ forms relatively few complexes compared with those of phosphines. Complexes with ammines, nitriles and diazoles like Au(NH3)2 and Au(RCN)2 are known but little studied. In linear Au(NH3)2, Au-N is 2.01-2.03 A [70a], [Au(NCPh)2]+ has been used as a labile source of other gold complexes [70b]. AuCl(piperidine) is a monomer with weak tetra-meric association in contrast AuX(py) (X = Cl, Br, I) are [Aupy2]+[AuX2] with a chain structure in the solid state (and Au-Au interactions), suggesting a close balance between factors for molecular and ionic structures [70c] (note also the tetrahydrothiophene complexes in section 4.10.6). 

A structurally characterized gold complex with a C5HPh4 ligand Au(r C5HPh4)(PPh3) (46a) was reported [66], An unusual trinuclear cluster 46b derived therefrom was also characterized by X-ray structural analysis. 

A second class of catalysts was prepared by deposition of TiCU and Mg metal on gold surfaces [91,117]. Mg deposition and subsequent TiCU exposure results in a complex structure with Mg metal being located at the gold interface and covered by a MgCl2 layer. On top of that TiCl species of differ-... 

Barber J., Elduque, A., Gimenez, R., Lahoz, F.J., Oro, L.A. and Serrano, J.L. (1998) (Pyrazolato)gold complexes showing room-temperature columnar mesophases. Synthesis, properties, and structural characterization. Inorganic Chemistry, 37, 2960-2967. 

Guzman, J. and Gates, B.C. (2003) Structure and reactivity of a mononuclear gold-complex catalyst supported on magnesium oxide. Angewandte Chemie International Edition, 42, 690-693. 

Kitadai, K., Takahashi, M., Takeda, M., Bhargava, S.K., Priver, S.Fl. and Bennett, M.A. (2006) Synthesis, structures and reactions of cyclometalated gold complexes containing (2-diphenylarsino-n-methyl)phenyl (n = 5, 6). Dalton Transactions, (21), 2560—2571. 

Terroba, R., Fernandez, E.J., Hursthouse, M.B. and Laguna, M. (1998) Dithiolate diphosphine polynuclear gold complexes. X-ray structure of [Au2( X-dppm) (C6F5)2(S2C6H4)]. Polyhedron, 17(15), 2433-2439. 

Assefa, Z Forward, J.M., Grant T.A., Staples, R.J., Hanson, B.E., Mohamed, A.A. and Fackler, J.P. Jr (2003) Three-coordinate, luminescent, water-soluble gold(l) phosphine complexes structural characterization and photoluminescence properties in aqueous solution. Inorganica Chimica Acta, 352, 31 5. 

Crane, W.S. and Beall, H. (1978) The structure of a large ring gold complex. Inorganica Chimica Acta, 31, L469-L470. 

Figure 8.26 Schematic formula (a) molecular single crystal X-ray diffraction structure (b), and solid state packing (c) ofthe cationic gold complex [Au bimy(Ci6H33) 2]Br H20. (Reproduced from Ref [52] by permission.)...

Hypothetical (carbene)gold(i) structures of intermediates and reaction coordinates have been calculated (B3LYP/ 6-31G and LAN2DZ levels) for (H3P)Au+-catalyzed cyclization reactions of terminal enynes. The endocyclic skeletal rearrangement reactions were found to proceed exclusively via cyclopropylcarbene complexes.240... 

Similar observations were made with bis[alkoxy(alkylamino)carbene]gold complexes, which are prepared by ring opening of trinuclear precursors with trifluoromethanesulfonic (triflic) acid. Through anion metathesis, several crystalline forms were obtained, the structures of which were determined. The triflate salt has a chain of cations in the crystal, while the chloroform solvate of a />-benzoquinolate contains only monomeric cations. In the solvent-free crystals, dimers are present (Scheme 59).251... 

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