Synthesis and crystal structure of the cluster (Et4N)[(Tp*)MoFe3S3(µ3-NSiMe3)(N3)3].

ABSTRACT

The title compound, tetra-ethyl-ammonium tri-azido-tri-µ3-sulfido-[µ3-(tri-methyl-sil-yl)aza-nediido][tris-(3,5-di-methyl-pyrazol-1-yl)hydro-borato]triiron(+2.33)molybdenum(IV), (C8H20N)[Fe3MoS3(C15H22BN6)(C3H9NSi)(N3)3] or (Et4N)[(Tp*)MoFe3S3(µ3-NSiMe3)(N3)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 µ3-bridging S atoms in the core. The Fe sites are in a distorted tetra-hedral coordination model, coordinating two µ3-bridging S atoms, one µ3-bridging N atom from Me3SiN2-, 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. C71, 9-18] function was applied. The solvent contribution is not included in the reported mol-ecular weight and density.