(NH4)2[Re2S16], a Soluble Metal Sulfide with Interesting Electronic Properties and Unusual Reactivity

A strong transannular Re-Re interaction and reactive metal-sulfur bonds characterize the title anion 1 (shown on the right without the two chelating S4-ligands). This surprising result explained by the existence of molecular orbitials arising from Re 5d and S 3p functions of similar energy are not only Re-Re bonding but also markedly delocalized. These findings underline the importance of the role of the metal center, especially in catalytically active metal sulfides.