Synthesis and Crystal Structure of a Tetranuclear Molybdenum(II) Silylamido Cluster

Treatment of molybdenum(II) chloride with the difunctional silylamide Li 2 Me 2 Si(NPh) 2 led to the formation of the tetranuclear cluster compound [Mo 4 {Me 2 Si(NPh) 2 } 4 ]. According to the X‐ray crystal structure determination, the central core of the cluster consists of four molybdenum atoms in a nearly rectangular arrangement. There are two μ 4 ‐κ‐ N,N,N ' ,N' ‐Me 2 Si(NPh) 2 2– ligands capping the Mo 4 rectangle and two μ 2 ‐Me 2 Si(NPh) 2 2– ligands located at opposite edges. The alternating Mo–Mo distances of 218.1(1) and 279.5(1) pm indicate the presence of a cyclobutadiyne type cluster with alternating Mo–Mo triple and single bonds.