Selenido osmium carbonyl cluster compounds. Structure, bonding, and reactivity of the electron-rich cluster Os4(CO)123-Se)2

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

33 Scopus Citations
View graph of relations

Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)4718-4722
Journal / PublicationInorganic Chemistry
Volume23
Issue number26
Publication statusPublished - 1984
Externally publishedYes

Abstract

The compound HOs3(CO)10(μ-SePh) (3) has been prepared (75% yield) by the reaction of Os3(CO)10(NCMe)2 with PhSeH. Under the conditions 160°C (3000 psi CO), 3 eliminates benzene and is transformed into the compounds Os3(CO)93-Se)2 (4) and Os(CO)5 in 95% yield. When irradiated (UV) under an atmosphere of CO, 3 loses benzene and is converted to Os3(CO)93-CO)(μ3-Se) (5) in 18% yield. When irradiated in the presence of Os(CO)5, 4 adds one Os(CO)4 moiety to form the compound Os4(CO)133-Se)2 (6) in 33% yield. At 125°C, 6 loses 1 mol of CO to form the cluster Os4(CO)123-Se)2 (7) quantitatively. 7 has been characterized by a single-crystal X-ray diffraction analysis: space group P1 (No. 2), a = 13.987 (4) Å, b = 16.371 (6) Å, c = 9.491 (6) Å, α = 106.04 (4)°, β = 90.31 (4)°, γ = 81.63 (3)°, V = 2065 (3) Å3, Z = 4, ρcalcd = 4.036 g/cm3. The structure was solved by direct methods and refined (4036 reflections, F2 ≥ 3.0σ(F2)) to the final residuals RF = 0.047 and RwF = 0.056. The molecule consists of a butterfly tetrahedral cluster of four osmium atoms, with triply bridging selenido ligands bridging the two open triangular faces. The metal-metal bonding is irregular, with two of the five metal-metal bonds being greater than 3.00 Å in length. 7 adds 1 mol of CO under mild conditions (25°C (1 atm CO)) to re-form 6 quantitatively. At 125°C, 7 oxidatively adds 1 mol of H2 to yield the compound H2Os4(CO)123-Se)2 (8) in 35% yield. 5 reacts with H2 at 125°C to form H2Os3(CO)93-Se) (9) in 39% yield. © 1984 American Chemical Society.