title: Synthesis and Isomeric Analysis of RuIIComplexes Bearing Pentadentate Scaffolds.
abstract: A RuII-pentadentate polypyridyl complex [RuII(κ-N5-bpy2PYMe)Cl]+(1+, bpy2PYMe = 1-(2-pyridyl)-1,1-bis(6-2,2'-bipyridyl)ethane) and its aqua derivative [RuII(κ-N5-bpy2PYMe)(H2O)]2+(22+) were synthesized and characterized by experimental and computational methods. In MeOH, 1+exists as two isomers in different proportions, cis (70%) and trans (30%), which are interconverted under thermal and photochemical conditions by a sequence of processes: chlorido decoordination, decoordination/recoordination of a pyridyl group, and chlorido recoordination. Under oxidative conditions in dichloromethane, trans-12+generates a [RuIII(κ-N4-bpy2PYMe)Cl2]+intermediate after the exchange of a pyridyl ligand by a Cl-counterion, which explains the trans/cis isomerization observed when the system is taken back to Ru(II). On the contrary, cis-12+is in direct equilibrium with trans-12+, with absence of the κ-N4-bis-chlorido RuIII-intermediate. All these equilibria were modeled by density functional theory calculations. Interestingly, the aqua derivative is obtained as a pure trans-[RuII(κ-N5-bpy2PYMe)(H2O)]2+isomer (trans-22+), while the addition of a methyl substituent to a single bpy of the pentadentate ligand leads to the formation of a single cis isomer for both chlorido and aqua derivatives [RuII(κ-N5-bpy(bpyMe)PYMe)Cl]+(3+) and [RuII(κ-N5-bpy(bpyMe)PYMe)(H2O)]2+(42+) due to the steric constraints imposed by the modified ligand. This system was also structurally and electrochemically compared to the previously reported [RuII(PY5Me2)X]n+system (X = Cl, n = 1 (5+); X = H2O, n = 2 (62+)), which also contains a κ-N5-RuIIcoordination environment, and to the newly synthesized [RuII(PY4Im)X]n+complexes (X = Cl, n = 1 (7+); X = H2O, n = 2 (82+)), which possess an electron-rich κ-N4C-RuIIsite due to the replacement of a pyridyl group by an imidazolic carbene.
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Gil-Sepulcre
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.
authors.forename: Jordan C
authors.initials: JC
authors.lastname: Axelson
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Aguiló
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Lluís
authors.initials: L
authors.lastname: Solà-Hernández
authors.affiliation: Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology , Av. Països Catalans 16, 43007 Tarragona, Catalonia, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Francàs
authors.affiliation: Institut de Química Computacional i Catàlisi and Departament de Química, Facultat de Ciències, Universitat de Girona , 17003 Girona, Catalonia, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Poater
authors.affiliation: Institut de Química Computacional i Catàlisi and Departament de Química, Facultat de Ciències, Universitat de Girona , 17003 Girona, Catalonia, Spain.
authors.forename: Lluís
authors.initials: L
authors.lastname: Blancafort
authors.affiliation: Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology , Av. Països Catalans 16, 43007 Tarragona, Catalonia, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Benet-Buchholz
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Guirado
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Lluís
authors.initials: L
authors.lastname: Escriche
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.|Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology , Av. Països Catalans 16, 43007 Tarragona, Catalonia, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Llobet
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Roger
authors.initials: R
authors.lastname: Bofill
authors.affiliation: Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès, Barcelona, Catalonia, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Sala