Synthesis and Structures of [Mo12E16(PEt3)10] (E = S, Se)

Abstract

AbstractDodecanuclcar cluster complexes [Mo12S16(PEt3)10] 1 and [Mo12Se16(PEt3)10] 2 have been prepared by the reactions of [Mo6S8(PEt3)6] with sulfur or [Mo6Se8(PEt3)6] with Cp2TiSe5, respectively, in toluene at refluxing temperature. The structures have been determined at 173 K by X‐ray crystallography. The compound 1·3CHCl3 crystallizes in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document}, with a = 14.859(5) Å, b = 15.868(4) Å, c = 14.200(7) Å, α = 100.58(3)°, β = 117.58(3)°, γ = 79.53(2)°, V = 2899(1) Å3, and Z = 1. Full‐matrix least‐squares refinement using 9016 observed reflections (Io > 2σ(Io)) gave R = 0.056, and Rw = 0.045. The data for 2·2CHCl3 are: triclinic, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document}, a = 15.737(4) Å, b = 18.763(9) Å, c = 13.062(4) Å, α = 102.45(3)°, β = 128.54(2)°, γ = 69.49(3)°, V = 2825 Å3, Z = 1, R = 0.096, and Rw = 0.120 for 5922 reflections (Io > 2σ(Io)). The cluster complexes 1 and 2 have two octahedral molybdenum cluster units linked by the rhomboidal intercluster Mo2(μ4‐E)2 bonding. The intercluster Mo—Mo distances in 1 are 3.419 Å and 2 3.551 Å. The cyclic voltammetry of 1 and 2 shows two oxidation and two reduction steps separated as large as 380–490 mV. The UV‐Vis spectra of the dodecanuclear cluster complexes 1 and 2 have an extra weak band at around 744 nm which is absent in the starting octahedral cluster complexes.