Allene-derived gold and platinum complexes: synthesis and first applications in catalysis

Abstract

Novel metal carbene complexes made from bis(pyridyl)allenes have promising catalytic activity.

Precious metal complexes of bis(pyridyl)allenes: synthesis and catalytic and medicinal applications

“…Attempts to improve the efficiency of the reaction, for example, by increasing the temperature, resulted in full conversion into the cyclic product 5a, observed in our previous work. 28 On the other hand, reaction of 1b in refluxing methanol yielded a mixture of allene-containing complex 4b and mixture of isomers of the cyclised 5b that could be easily separated afterwards, as previously reported. 28 Characterisation of 4a-b confirmed the presence of the allene moiety and the N,N-chelating character of these complexes.…”

“…The more reactive 3b underwent cycloplatination under reducing conditions losing the allene core in the process. 28 Inertness of 3ab under milder reduction conditions might be explained by their quite negative Pt(IV)/Pt(II) reduction potentials found at −1.0 V and −1.1 V, respectively for 3a and 3b, as measured by cyclic voltammetry of these complexes (see ESI, † section 2.2).…”

“…We previously reported that in the presence of Au(I) sources these ligands undergo cyclisation triggered by activation of the allene unit by the carbophilic Au(I) and attack of the pyridyl group onto the terminal carbon of the allene. 28 However, the different nature of the Au(III) centre allowed the access to unprecedented Au(III) complexes with the allene moiety intact (Scheme 3).…”

“…3a, bottom). 28 To date applications of bis( pyridyl)allene-based metal systems remain totally unexplored, not only in the area of catalysis, but also in their use in a biological context. This latter application has also been completely unchartered in reported phosphine analogues, which gives this work additional signifi- cance.…”

Synthesis and photophysical properties of linear gold(i) complexes based on a CCC carbene

“…Gold complexes of carbenes lacking this heteroatom stabilization have been reported only recently. 16 The groups of Fensterbank 17 and Munoz 18 reported that cycloisomerization of allenylpyridines allows the isolation of gold and platinum complexes of indolizin-2-ylidene (Indolizy) type carbenes, that is carbenes with the heteroatom in 3position relative to the carbene-C. 19 Here we report new Indolizy carbene gold complexes having chloride and carbazolide anionic ligands in order to study the effect of carbenes with remote heteroatom stabilization on the photoluminescent properties of the CMA materials.…”