Gold cyclometallated complexes

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. 

Further examples of emissive cyclometallated gold(III) complexes are [Au(L)Cl] (L = tridentate carbanion of 4 -(4-methoxyphenyl)-6 -phenyl-2,2 -bipyridine) [53], as well as mono- and binuclear bis-cyclometallated gold(III) complexes, namely [Au (C N C )L ]" (C N C = tridentate dicarbanion of 2,6-diphenylpyridine L = depro-tonated 2-mercaptopyridine (2-pyS ), n = 0 L = PPh3 or 1-methylimidazole, n = 1) and [Au2(C N C )2(P P)](C104)2 (P P = dppm, dppe) respectively [54]. The crystal structures of the binuclear derivatives show intramolecular interplanar separations of 3.4 A between the [Au(C N C)] moieties, implying the presence of weak n-n interactions. The mononuclear complexes show absorption with vibronic structure at 380-405 nm (e > 10 cm ), attributed to metal-perturbed intraligand transition. 

Chan, C.-W., Wong, W.-T. and Che, C.-M. (1994) Gold(lll) photooxidants. Photophysical, photochemical properties, and crystal structure of a luminescent cyclometallated gold(lll) complex of 2,9-diphenyl- 1,10-phenanthroline. Inorganic Chemistry, 33, 1266-1272. 

The Au(ll) oxidation state was also observed in cyclometalated gold dimers [386, 387] and in gold complexes of hA(diphenylphosphino)amine [388]. The specific feature of these Au(ll) complexes is that their 6 - A q relation is located midway between that of Au(l) and Au(lll) complexes. 

The Chemistry of Cyclometallated Gold(lll) Complexes with C,N-Donor... 

Cyclometallated gold(III) dihalide complexes also act as useful precursors for the synthesis of gold(III) complexes with thiolate and other sulfur donor ligands. The cyclometallated ligand stabilises the gold(III) centre towards reduction, which is important due to the reducing potential of sulfur-based ligands. 

Sanna G, Pilo MI, Spano N, Minghetti G, Cinellu MA, Zucca A, Seeber R (2001) Electrochemical behaviour of cyclometallated gold(III) complexes. Evidence of transcyclometalla-tion in the fate of electroreduced species. J Organomet Chem 622 47-53... 

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