title: Theoretical and experimental studies of diruthenium tetracarboxylates structure, spectroscopy, and electrochemistry.
abstract: Quantum mechanical calculations at the density functional theory (DFT) level have been performed on diruthenium tetracarboxylates of different levels of molecular complexity: from unsolvated monomers to oligomers. The agreement between the calculated and experimental molecular structures and vibrational modes of the simple [Ru2(micro-O2CCH3)4]0/+ and [Ru2(micro-O2CCH3)4(H2O)2]0/+ systems made us confident in our calculation methodology. Therefore, it has been applied to the analysis of two different kinds of properties of these compounds: the trends in the UV/vis spectroscopy and electrochemistry along the [Ru2(micro-O2CCH3)4X2]- (X=Cl-, Br-, I-) series, and the crystalline polymorphism related to the polymeric strand conformation in extended Ru2(micro-O2CR)4Cl compounds. For the [Ru2(micro-O2CCH3)4X2]- series, we report new spectroscopic and electrochemical results and interpret the trends on the basis of time dependent DFT-polarized continuum model calculations, local charge and spin analysis, and X donor properties. As far as the polymeric conformation is concerned, it has been previously suggested that the Ru-Cl-Ru angle results from a compromise between packing, orbital overlap, and microsegregation. Our calculations on [Ru2(micro-O2CCH3)4Cl]2Cl- and [Ru2(micro-O2CCH3)4Cl]3Cl- oligomers provide insights on the influence of the first two factors on the strand conformation and allows a suggestion on what is the equatorial aliphatic chain's influence on this issue.
authors.affiliation: INQUIMAE, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pab. II, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
authors.forename: Maria Ana
authors.initials: MA
authors.lastname: Castro
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Roitberg
authors.forename: Fabio D
authors.initials: FD
authors.lastname: Cukiernik
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D004583:Electrons; D054879:Halogenation; D050866:Liquid Crystals / Q000737:chemistry; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014732:Vibration
chemical_list: D002264:Carboxylic Acids; D011108:Polymers; D012997:Solvents; D012428:Ruthenium