134654-72-1Relevant articles and documents
Heteroatom exchange reactions in imidoosmium(II) systems: Cleavage of Os-N multiple bonds and formation of Os-X bonds (X = O, S, C)
Michelman, Richard I.,Ball, Graham E.,Bergman, Robert G.,Andersen, Richard A.
, p. 869 - 881 (2008/10/08)
The monomeric imido complex CymOsN-t-Bu (2) (Cym = η6-p-cymene) was used as a convenient precursor in exchange reactions with a variety of H-X bonds (X = O, S, C). Complex 2 reacts with alkoxides HOCMe(CF3)2, pinacol, catechol, and 1,2-(H2N)(HO)C6H4 to give CymOs(NH-t-Bu)[OCMe(CF3)2] (4), CymOs[OC(CH3)2C(CH3)2O] (5), CymOs[1,2-O2C6H4] (6), and CymOs[1,2-O(HN)C6H4] (7), respectively. CymOs(O-t-Bu)2 (3) was not formed by this method but was generated by treatment of [CymOsCl2]2 (1) with KO-t-Bu. Addition of H2N-t-Bu to 3 gave 2, and reaction of 5 with catechol gave 6. Complex 6 adds PMe3 to give CymOs[1,2-O2C6H4](PMe3) (8). Catechol, 1,2-(H2N)2C6H4, or H2N-p-tol hydrogen bond or coordinate to the metal in 6 or CymOs[1,2-(NH)2C6H4] (10). Reactivity patterns generally correlate with the pKa of the substrate, but other factors are also involved. Several analogous thiolate complexes were also prepared. For example, imido complex 2 or bis(tert-butoxide) 3 reacted readily with t-Bu-SH to give CymOs(S-t-Bu)2 (13). The analogous osmium complexes with 2,6-Me2C6H3 and 2,4,6-Me3C6H2 groups attached to the sulfur atoms (14 and 15, respectively) were obtained by treatment of imido complex 2 with the appropriate thiols. However, reaction of 2 with p-tol-SH gave the dimeric thiolate complex [CymOs(S-p-Me-C6H4)2]2 (16). Complex 2 also reacts with carbon acids. The more acidic C-H bond of H2C(COMe)2 (acacH) caused the addition of 2 mol of diketone with tert-butylamine loss to give CymOs[CH(COMe)2][(OC(Me))2CH-O,O] (18) whereas the weaker acid (H2C(CO2Me)2) added only once across the Os-N bond to give CymOs(NH-t-Bu) [CH(CO2Me)2] (17). Treatment of dichloro dimer [CymOsCl2]2 with K2CO3 and acacH quantitatively provided yellow CymOs(acac-O,O)Cl (19). Monoacetylacetonato complex 19 was treated with AgOAc (Ac = COMe) to give CymOs(acac)(OAc) (21). Dimethyl malonate complex 17 was independently treated with acacH and H2C(CO(Ph))2 to give CymOs[CH(C02Me)2][(OC(Me))2CH] (22) and bright red CymOs[CH(CO2Me)2][(OC(Ph))2CH] (23). Carbon-proton NMR coupling data provided evidence for the presence of carbon-metal bound diketonate ligands in 17, 18, 22, and 23.