Abstract

The trinuclear carbonyl clusters [Fe3(CO)12], [Ru3(CO)12], [Os3(CO)12] and [Os3(CO)10(MeCN)2] react with benzo[b]tellurophene under mild conditions, in refluxing tetrahydrofuran, to give compounds containing the open-chain ligands C6H4CHCHTe or the fragments Te and C8H6 as bridging ligands. The following compounds were isolated and characterised; [Os3(?-C8H6Te)(CO)10] (1), [Os2(?-C8H6Te)(CO)6] (2), [Os2(?-C8H6)(CO)6] (3) and [Os4(?-C8H6)(?3-Te)(CO) 11] (4), which were obtained from the reaction of [Os3(CO)12] and benzo[b]tellurophene. [Ru3(?-C8H6)(CO)8] (5) (X-ray reported previously) [Ru2(?-C8H6Te)(CO)6] (6), [Ru2(?-C8H6)(CO)6] (7) and [Ru4(?3-Te)(?-C8H6)(CO) 11] (8) were derived from the reaction of [Ru3(CO)12] and benzo[b]tellurophene; [Fe2(?-C8H6Te)(CO)6] (9) and [Fe2(?-C8H6)(CO)6] (10) were obtained from [Fe3(CO)12]. All the compounds were characterised by 1H NMR and 1R 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 C6H4CHCHTe 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 ?3-Te ligand and a C8H6 bridging ligand. This cluster contains a Te-capped triangle of ruthenium atoms and there is a spiked ruthenium atom supporting the bridging C8H6 ligand. In this case the Te atom has been extruded from the heterocycle but remains in the cluster. Crystal data: 1: monoclinic, space group P21/a, a = 12.326(7), b = 13.821(4), c = 13.538(5) Å, ? = 107.01(3)°, Z = 4; 4: monoclinic, space group P21/n, a = 16.740(2), b = 8.684(3), c = 18.536(4) Å, ? = 112.87(1)°, Z = 4; 6: monoclinic, space group P21/a, a = 12.291(3), b = 12.098(5), c = 22.880(4) Å, ? = 95.24(2)°, Z = 8; 8: monoclinic, space group P21/n, a = 14.376(4), b = 11.268(4), c = 15.313(4) Å, ? = 96.27(2)°, Z = 4; 9: monoclinic, space group P21/a, a = 12.094(3), b = 11.737(3), c = 22.632(4) Å, ? = 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? (I), respectively.