Synthesis and crystal structure of the cluster (Et 4 N)[(Tp*)MoFe 3 S 3 (μ 3 -NSiMe 3 )(N 3 ) 3 ].

The title compound, tetra-ethyl-ammonium tri-azido-tri-μ 3 -sulfido-[μ 3 -(tri-methyl-sil-yl)aza-nediido][tris-(3,5-di-methyl-pyrazol-1-yl)hydro-borato]triiron(+2.33)molybdenum(IV), (C 8 H 20 N)[Fe 3 MoS 3 (C 15 H 22 BN 6 )(C 3 H 9 NSi)(N 3 ) 3 ] or (Et 4 N)[(Tp*)MoFe 3 S 3 (μ 3 -NSiMe 3 )(N 3 ) 3 ] [Tp* = tris-(3,5-di-methyl-pyrazol-1-yl)hydro-bor-ate(1-)], crystallizes as needle-like black crystals in space group P . In this cluster, the Mo site is in a distorted octa-hedral coordination model, coordinating three N atoms on the Tp* ligand and three μ 3 -bridging S atoms in the core. The Fe sites are in a distorted tetra-hedral coordination model, coordinating two μ 3 -bridging S atoms, one μ 3 -bridging N atom from Me 3 SiN 2- , and another N atom on the terminal azide ligand. This type of heterometallic and heteroleptic single cubane cluster represents a typical example within the Mo-Fe-S cluster family, which may be a good reference for understanding the structure and function of the nitro-genase FeMo cofactor. The residual electron density of disordered solvent mol-ecules in the void space could not be reasonably modeled, thus the SQUEEZE [Spek (2015). Acta Cryst . C 71 , 9-18] function was applied. The solvent contribution is not included in the reported mol-ecular weight and density.