Synthesis and Structure of the Clusters [Hg 2 (μ—SePh) 2 (SePh) 2 (PPh 3 ) 2 ] and [Hg 3 Br 3 (μ—SePh) 3 ] · 2 DMSO

The compounds [Hg 2 (μ—SePh) 2 (SePh) 2 (PPh 3 ) 2 ] ( I ) and [Hg 3 Br 3 (μ—SePh) 3 ] · 2 DMSO ( II ) are formed by reactions of [Hg(SePh) 2 ] with PPh 3 in THF( I ) or with HgBr 2 in DMSO ( II ) at room temperature. X—ray crystallography reveals that the cluster I consists of a distorted square built by each two Hg and Se atoms. The Hg atoms have almost tetrahedral co‐ordination environments formed by selenium atoms of two (μ‐ — SePh) ligands and Se and P atoms of terminal — SePh and PPh 3 ligands. The compound II is a six‐membered ring with alternating Hg and Se atoms in the chair conformation. Two DMSO molecules occupy positions below and above the [Hg 3 Se 3 ] ring with the oxygen atoms directed to the centre of the ring.