title: Elongated Dihydrogen versus Compressed Dihydride in Osmium Complexes.
abstract: Small modifications on the co-ligands of complexes containing two coordinated hydrogen atoms can determine the elongated dihydrogen versus compressed dihydride nature of these species and therefore their chemical behavior. 2,6-diphenylpyridine favors the formation of the osmium(IV) cation [OsH2(C6H4pyPh)(PiPr3)2]+, whereas 2-phenoxy-6-phenylpyridine, which contains an oxygen atom between the heterocycle and one of the phenyl groups, stabilizes the osmium(II) elongated dihydrogen species [Os(C6H4pyOPh)(η2-H2)(PiPr3)2]+. In contrast to the latter, the former shows a marked tendency to undergo reductive elimination of the heterocycle.
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Beatriz
authors.identifier: http://orcid.org/0000-0002-1621-6434
authors.initials: B
authors.lastname: Eguillor
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Miguel A
authors.identifier: http://orcid.org/0000-0002-4829-7590
authors.initials: MA
authors.lastname: Esteruelas
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Virginia
authors.identifier: http://orcid.org/0000-0001-6843-2799
authors.initials: V
authors.lastname: Lezáun
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Montserrat
authors.identifier: http://orcid.org/0000-0003-0381-0917
authors.initials: M
authors.lastname: Oliván
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Enrique
authors.identifier: http://orcid.org/0000-0003-2094-719X
authors.initials: E
authors.lastname: Oñate
keywords: C−H activation; agostic interactions; dihydrogen; hydrides; osmium