Ring opening and extrusion of tellurium atoms in the reaction of benzo[ b]tellurophene with trinuclear iron, ruthenium and osmium clusters: X-ray crystal structures of [Os 2(μ-C 8H 6Te)(CO) 10], [Os 4( μ-C 8H 4)( μ3-Te)(CO 11], [Ru( μ-C 8H 6Te)( CO) 6)], [Ru 4( μ3-Te)( μ-C 8H 6)(CO) 11] and [ Fe2) μ-C 8H 6Te(CO) 6

Abstract

The trinuclear carbonyl clusters [Fe 3(CO) 12], [Ru 3(CO) 12], [Os 3(CO) 12] and [Os 3(CO) 10(MeCN) 2] react with benzo[ b]tellurophene under mild conditions, in refluxing tetrahydrofuran, to give compounds containing the open-chain ligands C 6H 4CHCHTe or the fragments Te and C 8H 6 as bridging ligands. The following compounds were isolated and characterised: [Os 3(μ-C 8H 6Te)(CO) 10] ( 1), [Os 2(μ-C 8H 6Te)(CO) 6] [Os 2(μ-C 8H 6)(CO) 6] ( 3) [Os 4 μ-C 8H6)( μ 3-Te(CO) 11] ( 4), which were obtained were obtained from the reaction of [Os 3(CO) 12] and benzo[ b]tellurophene. [Ru 3(μ-C 8H 6)(CO) 8)] ( 5) (X-ray reported previously) [Ru 2(μ-C 8H 6Te)(CO) 6] ( 6), [Ru 2(μ-C 8H 6] ( 7) and [Ru 4( μ 3-Te( μ-C 8H 6)(CO) 11] ( 8) were derived from the reaction of [Ru 3(CO) 12] and benzo[ b]tellurophene; [Fe 2(μ-C 8H 6Te)(CO) 6] ( 9) and [Fe 2(μ-C 8H 6)(CO) 6] ( 10) were obtained from [Fe 3(CO) 12]. All the compounds were characterised by 1H NMR and IR spectroscopy in solution and 1, 4, 6, 8 and 9 were characterised by X-ray diffraction methods in the solid state. All the clusters were shown to have had a TeC bond broken to give the C 6H 4CHCHTe as a bridging ligand linking two metal atoms. Cluster 8 was shown by single-crystal X-ray diffraction methods to have had both TeC bonds broken to give a μ 3-Te ligand and a C 8H 6 bridging ligand. This cluster contains a Te-capped triangle of ruthenium atoms and there is a spiked ruthenium atom supporting the bridging C 8H 6 ligand. In this case the Te atom has been extruded from the heterocycle but remains in the cluster. Crystal data: 1: monoclinic, space group P2 1/a, a=12.326(7), b=13.821(4), c=13.538(5) A ̊ , β=107.01(3)°, Z=4; 4: monoclinic, space group P2 1/n, a=16.740(2), b=8.684(3), c=18.536(4) A ̊ , β=112.87(1)°, Z=4; 6: monoclinic, space group P2 1/a, a=12.291(3), b=12.098(5), c=22.880(4) A ̊ , β=95.24(2)°, Z=8 ; 8: monoclinic, space group P2 1/n, a=14.376(4), b=11.268(4), c=15.313(4) A ̊ , β=96.27(2)°, Z=4 ; 9: monoclinic, space group P2 1/a, a=12.094(3), b=11.737(3), c=22.632(4)r A ̊ , β=96.66(2)°,Z=8 . The structures were solved by direct methods and were refined by full-matrix least-squares to R=0.0309, 0.0364, 0.0348, 0.0220 and 0.0410 for 4073, 3628, 3414, 2005 and 4985 reflections with I>3 σ( I), respectively.