Synthesis, Structure, and Characterization of N-Ligated Mo6S8L6 Cluster Complexes. Molecular Precursors to Chevrel Phases

Shane J. Hilsenbeck, Victor G. Young, Robert E. McCarley

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


A modified method has been developed for the synthesis of the Mo6S8 cluster unit in one step from Mo6Cl12 via reaction with NaSH and NaOBu in refluxing n-BuOH-pyridine. The ligand-deficient Na2xMo6S8+x(py)y (1) serves as a convenient starting material for the preparation of the amine complexes Mo6S8L6, with L = pyridine (2), pyrrolidine (4), and piperidine (5). Although propylamine readily dissolves the ligand-deficient starting material, only amorphous Mo6S8(PrNH2)6-x (3) could be isolated. However, the latter acts as a facile reactant for the preparation of the other complexes by ligand substitution. Crystallographic data for the complexes are as follows: Mo6S8(py)6·2py (2), cubic, Pa3, a = 16.994(2) Å, Z = 4, R = 0.0381, Rw = 0.0351; Mo6S8(pyrr)6·pyrr (4), tetragonal, I41/a, a = 29.933(4) Å, c = 23.697(8) Å, Z = 16, R = 0.0675, wR2 = 0.2034; Mo6S8(pip)6·7pip, (5), tetragonal, I4, a = 19.421(2) Å, c = 22.584(3) Å, Z = 8, R = 0.0317, Rw = 0.0366. These complexes all show strong bands in the IR at 380 ± 5 cm-1 and in the Raman at 414 ± 4 cm-1, assigned as predominantly Mo-S stretching modes. XP spectra give characteristic binding energies at 227.7 ± 0.1 (Mo 3d5/2), 230.8 ± 0.1 (Mo 3d3/2), 225.1 ± 0.3 (S 2s), 160.6 ± 0.1 (S 2p3/2), and 161.8 ± 0.1 (S 2p1/2) eV. Mo-Mo and Mo-S bond distances show little variation among the complexes, with average values of 2.647 and 2.454 Å, respectively. The average Mo-N bond distance, 2.297 Å, indicates rather weak bonding of these N-donor ligands.

Original languageEnglish (US)
Pages (from-to)1822-1832
Number of pages11
JournalInorganic Chemistry
Issue number9
StatePublished - Apr 1 1994


Dive into the research topics of 'Synthesis, Structure, and Characterization of N-Ligated Mo<sub>6</sub>S<sub>8</sub>L<sub>6</sub> Cluster Complexes. Molecular Precursors to Chevrel Phases'. Together they form a unique fingerprint.

Cite this