Multinuclear C4B Ring Complexes, Clusters, and Extended Systems

2 Multinuclear C4B Ring Complexes, Clusters, and Extended Systems 

Reaction of the heterocubane cluster 14 (R = Ph) with (Cp Rhl2)2, a reagent that functions both as a Lewis acid (the metal center) and a Lewis base (the iodide ligands), generates the dirhodium complex 18. Complex 14 also adds to l,l-bis(diphenylphosphinoferrocene) to form the cyclic species 19.8 

In yet another facet of heterocubane chemistry, 14 (R = Ph) has been found to react with Ag+ in acetonitrile to form the salt (MeCN)3Rh(C4H4B-Ph)+ BF4 20, which in turn combines with arenes to generate (arene)Rh(C4H4B-Ph)+ BF4- products.9 Under vacuum, 20 loses MeCN to form the polymer 21, the phenyl group migrating to the Rh center of a different fragment. 

The first mixed metal borole cluster 22, which contains a planar Re2Pd2 array, was prepared via reaction of the [(r/s-H4C4B-Ph)Re(CO)3] anion with PdCl2(NCPh)2.25 In this electron-deficient system, the Pd atoms are formally 14e centers, stabilized by metal-metal binding with each other and with the Re atoms. 

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