Stabilization of Niobium(0) and Tantalum(0) in Mixed Metal Clusters containing Silver Atoms

The structures of 1 are characterized by nearly equilateral triangles formed by the atoms of the two metals. One triangle is inscribed in the other. The central portion of the structure thus displays strong similarity to the (111) plane of a close-packed metal structure. Compounds 1a and 1b are the first structurally characterized Nb0 and Ta0 clusters without bridging ligands (dmpe = Me2PCH2CH2PMe2). [AgM(CO)4(dmpe)]3 1a, M = Nb; 1b, M = Ta