This report outlines the investigation of the iClick mechanism between gold(i)-azides and gold(i)-acetylides to yield digold triazolates. Isolation of digold triazolate complexes offer compelling support for the role of two copper(i) ions in CuAAC. In addition, a kinetic investigation reveals the reaction is first order in both Au(i)-N3 and Au(i)-C[triple bond, length as m-dash]C-R, thus second order overall. A Hammett plot with a ρ = 1.02(5) signifies electron-withdrawing groups accelerate the cycloaddition by facilitating the coordination of the second gold ion in a π-complex. Rate inhibition by the addition of free triphenylphosphine to the reaction indicates that ligand dissociation is a prerequisite for the reaction. The mechanistic conclusions mirror those proposed for the CuAAC reaction.

Metal-azide-metal-acetylide cycloaddition (iClick) reactions to synthesize heterotrimetallics and an unexpected novel tetranuclear gold(I) complex, are described. In addition, a discussion regarding the connection between traditional azide-alkyne cycloaddition reactions and iClick is presented focusing on applications towards linking multiple metal ions.

a b s t r a c tThe iClick (inorganic click) reactions between gold-acetylides and group 9 transition metal-azide complexes are presented. Complexes [Rh(CO)(PPh 3 ) 2 ][PPh 3 Au](3 (5). Complexes 3, 4, and 6 have been characterized by a combination of NMR spectroscopies, crystallography and combustion analysis.Published by Elsevier Ltd.

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