Vertex-Fused Clusters Featuring a Flattened Butterfly

In an effort to exploit the reactive chalcogen centers (Se or S) of preformed metallaheteroboranes [Cp*Ta(EPh)(2){B4H8}] (Cp*eta(5)-C5Me5; 1, E = Se; 2, E = S) toward cluster growth reactions, we have carried out the photolysis of tantallaheteroboranes 1 and 2 with the group 6 metal carbonyls [M(CO)(5)center dot THF] (M = Mo, W). The reactions yielded the vertex-fused metallaheteroborane clusters [{(CO)(4)M(EPh)(2)}Cp*Ta{B4H8}] (3, E= Se, M = Mo; 4, E = Se, M = W; 5, E = S, M = Mo; 6, E = S, M = W). Clusters 3-6 comprise square-pyramidal {TaB4} and butterfly {TaME2} cores having a common Ta vertex. All of the butterfly cores of these fused metallaheteroboranes 3-6 are almost flat, in which the dihedral angle between the planes W1-S1-Ta1 and W1-S1'-Ta1 of 6 was observed to be 175.32 degrees.

Automated summary

In this study, photolysis was used to exploit the reactive chalcogen centers in preformed metallaheteroboranes for cluster growth reactions, resulting in the synthesis of vertex-fused metallaheteroborane clusters. These clusters consist of square-pyramidal metal-boron cores and butterfly metal-sulfur cores.