Cooperative Effects Of Electron Donors And Acceptors For The Stabilization Of Elusive Metal Cluster Frameworks: Synthesis And Solid-State Structures Of [Pt-19(Co)(24)(Mu(4)-Aupph3)(3)](-) And [Pt-19(Co)(24){Mu(4)-Au-2(Pph3)(2)}(2)]

The anionic cluster [Pt-19(CO)(22)](4-) (1), of pentagonal symmetry, reacts with CO and AuPPh3+ fragments. Upon increasing the Au:Pt-19, molar ratio, different species are sequentially formed, but only the last two members of the series could be characterized by X-ray diffraction, namely, [Pt-19(CO)(24)(mu(4)-AuPPh3)(3)](-) (2) and [Pt-19(CO)(24){mu(4)-Au-2(PPh3)(2)}(2)] (3).The metallic framework of the starting cluster is completely modified after the addition of CO and AuL+, and both products display the same platinum core of trigonal symmetry, with closely packed metal atoms. The three AuL+ units cap three different square faces in 2, whereas four AuL+ fragments are grouped in two independent bimetallic units in the neutral cluster 3. Electrochemical and spectroelectrochemical studies on 2 showed that its redox ability is comparable with that of the homometallic 1.