title: N-h and N-C bond activation of pyrimidinic nucleobases and nucleosides promoted by an osmium polyhydride.
abstract: Complex OsH(6)(P(i)Pr(3))(2) (1) reacts with 1-methylthymine and 1-methyluracil to give OsH(3)(P(i)Pr(3))(2)(nucleobase') (2, 3) containing the deprotonated nucleobases (nucleobase') κ(2)-N,O coordinated by the nitrogen atom at position 3 and the oxygen bonded to the carbon atom of the ring at position 4. Similarly, the reactions of 1 with thymidine, 5-methyluridine, deoxyuridine, and uridine lead to OsH(3)(P(i)Pr(3))(2)(nucleoside') (4-7) with the deprotonated nucleoside (nucleoside') κ(2)-N,O coordinated by the nitrogen atom at position 3 and the oxygen bonded to the carbon atom at position 4 of the nucleobases. Treatment of complexes 5 and 7, containing nucleosides derived from ribose, with OsH(2)Cl(2)(P(i)Pr(3))(2) (8) in the presence of Et(3)N affords dinuclear species OsH(3)(P(i)Pr(3))(2)(nucleobase')-(ribose)(P(i)Pr(3))(2)H(2)Os (9, 10) formed by two different metal fragments. Complex 1 also promotes the cleavage of the N-C bond of 2-7 to give the dinuclear species {OsH(3)(P(i)Pr(3))(2)}(2)(nucleobase'') (11, 12) with the nucleobase skeleton (nucleobase'') κ(2)-N,O coordinated to both metal fragments. These compounds can be also prepared by reaction of 1 with 0.5 equiv of thymine and uracil. The use of 1:1 hexahydride:nucleobase molar ratios gives rise to the preferred formation of the mononuclear complexes OsH(3)(P(i)Pr(3))(2)(nucleobase''') (13, 14; nucleobase''' = monodeprotonated thymine or uracil). The X-ray structures of complexes 6, 11, and 14 are also reported.
authors.affiliation: Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain. maester@unizar.es
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Esteruelas
authors.forename: Jorge
authors.initials: J
authors.lastname: García-Raboso
authors.forename: Montserrat
authors.initials: M
authors.lastname: Oliván
authors.forename: Enrique
authors.initials: E
authors.lastname: Oñate
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry; D009705:Nucleosides / Q000737:chemistry*; D009992:Osmium / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D009705:Nucleosides; D011743:Pyrimidines; D009992:Osmium; D009584:Nitrogen