Synthesis, Structure and Reactivity of Electron Deficient Triosmium Cluster Bearing 2,6-Dimethylbenzothiazolide Ligand

Reaction of [Os 3 (CO) 10 (NCMe) 2 ] with 2,6-dimethylbenzothiazole at room temperature affords [Os 3 (CO) 10 ( μ -H){ μ - η 2 -C 7 H 2 NS(Me) 2 }] ( 1 ) in 45% yield. Decarbonylation of 1 in refluxing toluene furnishes the electron-deficient cluster [Os 3 (CO) 9 ( μ -H){ μ 3 - η 2 -C 7 H 2 NS(Me) 2 }] ( 2 ) in almost quantitative yield. Treatment of 2 with PPh 3 at 40 °C gives the addition product [Os 3 (CO) 9 (PPh 3 )( μ -H){ μ - η 2 -C 7 H 2 NS(Me) 2 }] ( 3 ) in 85% in which the PPh 3 ligand is coordinated to the rear osmium atom. A similar treatment of 2 with P(OMe) 3 gives [Os 3 (CO) 9 {P(OMe) 3 }( μ -H){ μ - η 2 -C 7 H 2 NS(Me) 2 }] ( 4 ) in 60% yield with P(OMe) 3 ligand also coordinated to the rear metal. Compounds 3 and 4 differ by the disposition of the hydride ligands. In compound 4 both the hydride and the heterocyclic ligands simultaneously bridge the same metal–metal edge whereas they bridge different metal–metal edges in 3 . Compounds 1 – 4 have been characterized by a combination of elemental analysis, infrared, NMR and mass spectral data together with single crystal X-ray diffraction studies for 3 . Compound 3 crystallizes in the monoclinic space group P 2 1 / n with a = 9.2659(10), b = 23.643(2), c = 16.382(3) Å, β = 91.324(12)°, Z = 4 and V = 3,587.8(8) Å 3 . Graphical Abstract Synthesis and reactivity of electron-deficient 2,6-dimethylbenzothiazole osmium cluster [Os 3 (CO) 9 ( μ -H){ μ 3 - η 2 -C 7 H 2 NS(Me) 2 }] ( 2 ) are described. Reaction of 2 with PR 3 (R = Ph, OMe) furnishes [Os 3 (CO) 9 (PR 3 )( μ -H){ μ - η 2 -C 7 H 2 NS(Me) 2 }] ( 3 , R = Ph; 4 , R = OMe) in which the PR 3 ligand is coordinated to the rear osmium atom.