New synthetic routes for the preparation of the triangular trinuclear clusters of tungsten-containing bromine atoms as terminal ligands: Structural characterization of [W3S4Br3(depe)3]PF6�0.5C7 H8 and [W3S4Br3(depe)3]Br�2CH3OH

Abstract

Synthetic methods are reported for the preparation of compounds containing the trinuclear triangular cluster [W3S4Br3(depe)3[+. These involve reactions between WBr5 and NaB(C2 H5)3H or NaBH4 as reducing agent in THF, and subsequent addition of methanolic solutions of NaHS and depe ligand. Both compounds, [W3S3Br3(depe)3]PF6·0.5C7H8,1, and [W3S4Br3(depe)3]Br·2CH3OH,2, are characterized by x-ray single crystal studies. Compounds1 and2 crystallize in space group\(P\bar 1\). For1,a=10.427 (3) A,b=15.415(4) A,c=18.140(5) A, α=79.36(2)°, β=73.59(2)°, γ=81.54(2)°, andV=2734.8(2) A3;R=0.050 and for 2a=10.491(3) A,b=15.074(3) A,c=18.246 A, α=95.76(2)°, β=105.82(2)°, γ=98.18(2)°, andV=2718.4(3) A3;R=0.081. The two cations in1 and2 possess C3 symmetry. The W-W distances are in the range 2.783−2.891 A (for1) and 2.778−2.785 A (for2) and the average W-Br distances in1 and2 are 2.616[2] A and 2.594[4] A, respectively. Each metal atom in the [W3S4Br3(depe)3]+ ions is attached to one capping sulfur atom, two bridging sulfur atoms, one bromine atom, and one chelating depe ligand. One P atom in depe ligand istrans to μ3-S and the otherP atom istrans to a μ2-S atom. UV-Vis and NMR spectra for these compounds are also reported.