[(Cyclen)4Ru4(pz)4]9+: A Creutz−Taube Square
- 11 July 2002
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 124 (31), 9042-9043
- https://doi.org/10.1021/ja027114q
Abstract
The use of cyclen (1,4,7,10-tetraazacyclododecane) as a blocking ligand enables assembly of the mixed-valence square complex [(cyclen)4Ru4(pz)4]9+ (pz = pyrazine). A crystal structure determination shows the molecule to possess a regular square geometry wherein each Ru atom has an equivalent coordination environment. Consistent with the presence of one RuIII and three RuII centers, cyclic voltammetry reveals a single reversible reduction wave and three successive oxidation waves. The separation between the first oxidation and reduction waves indicates a comproportionation constant of Kc = 108.9 for the [(cyclen)4Ru6(pz)4]9+ square, suggesting a greater extent of electron delocalization than that observed for the Creutz−Taube ion. The closer spacing between oxidation waves suggests a lesser degree of delocalization in the [(cyclen)4Ru6(pz)4]10+ (Kc = 102.0) and [(cyclen)4Ru6(pz)4]11+ (Kc = 103.0) species, bearing the higher average oxidation states of Ru2.5+ and Ru2.75+, respectively.Keywords
This publication has 18 references indexed in Scilit:
- Trinuclear Pyrazine-Bridged Ruthenium Complexes: Syntheses, Electrochemistry, NIR−Vis Spectra, and Their Interpretation in Terms of a 5-Orbital−3-Parameter ModelInorganic Chemistry, 2002
- High-Nuclearity Metal-Cyanide Clusters: Assembly of a Cr8Ni6(CN)24 Cage with a Face-Centered Cubic GeometryJournal of the American Chemical Society, 2000
- Molecular Prussian Blue analogues: synthesis and structure of cubic Cr4Co4(CN)12 and Co8(CN)12 clustersChemical Communications, 1998
- Syntheses and Crystal Structures of Ruthenium Complexes of 1,4,8,11-Tetraazacyclotetradecane, Tris(2-aminoethyl)amine (tren), and Bis(2-aminoethyl)(iminomethyl)amine. A Microporous Layered Structure Consisting of {[K(tren)]2[RuCl6]}nn- and {(H5O2)4[RuCl6]}nn+Inorganic Chemistry, 1996
- The near- and mid-infrared spectrum of the Creutz-Taube ion in aqueous solution: an application of FTIR spectroelectrochemical techniquesJournal of the American Chemical Society, 1989
- The Creutz-Taube complex revisited: crystallographic study of the electron-transfer series (.mu.-pyrazine)decaamminediruthenium ([(NH3)5Ru(Pyz)Ru(NH3)5]n+ (n = 4-6))Inorganic Chemistry, 1985
- The Creutz-Taube complex revisitedJournal of the American Chemical Society, 1984
- Charge-transfer spectra of ruthenium(II) complexesInorganic Chemistry, 1971
- Synthesis and properties of pentaamminepyridineruthenium(II) and related pentaammineruthenium complexes of aromatic nitrogen heterocyclesJournal of the American Chemical Society, 1968
- Infra-red and Raman spectra ot the diazinesSpectrochimica Acta, 1957