53195-17-8Relevant articles and documents
Heterobi-, tri- and tetra-metallic cyanide-bridged complexes based on pentacarbonylcyanochromate(0) and penta-, cis-tetra- and fac-tri-ammineruthenium(III) groups: Optical metal-metal charge transfer and electrochemical characteristics
Laidlaw,Denning
, p. 51 - 58 (1996)
The heterobi-, tri- and tetra-metallic Robin-Day Class II mixed-valence complexes, [(OC)5Cr(μ-CN)Ru(NH3)5]2+ (CrRu), cis-[{(OC)5Cr(μ-CN)}2Ru(NH3) 4]+ (Cr2Ru) and fac-[{(OC)5Cr(μCN)}3Ru(NH3)3] (Cr3Ru) have been synthesised directly by coupling [Cr(CO)5CN]- with an appropriate penta-, tetra-or tri-ammineruthenium precursor and characterised by electrochemical, analytical and spectroscopic methods. The complexes exhibit solvent-ammine hydrogen-bonding induced solvatochromism in the MMCT energy which linearly varies with the Gutmann solvent donor number (DN) at 219, 158 and 116(±7) cm-1/DN respectively which corresponds to a linear variation of 51(± 6) cm-1/DN/NH3 group. Electrochemical and spectrosopic evidence points to the ligating equivalence of [Cr(CO)5CN]- and NH3 groups in this series. Cyclic and square-wave voltammograms, CV and SWV, show reversible couples at + 0.45 and -0.36 V (versus ferrocene) for the chromium(0/I) and ruthenium(III/II) potentials in the complex set. Dispersion in CV and peak broadening in SWV, for CrxRu (x = 2,3), indicate weak Cr-Cr coupling through the ammineruthenium centre corresponding to a separation of ～ 65 mV. We report electrochemical data for [(OC)5Cr(μ-CN)Os(NH3)5]2+ (CrOs) and its visibly spectacular solvatochromism (188 cm-1/DN) from blue to purple, red, orange and yellow colourations.
The unusually fast reactions between ruthenium(III)-ammine complexes and NO revisited
Czap, Almut,Van Eldik, Rudi
, p. 665 - 671 (2003)
The kinetics of the unusually fast reactions between [RuIII(NH3)5X](3-n)+ (Xn- = Cl-, NH3, H2O) and NO were reinvestigated in acidic aqueous solution in order to clarify the underlying reaction mechanism. The measured second-order rate constants (kNH3 = 0.30 ± 0.01 M-1 s-1, kH2O = 55.6 ± 3.2 M-1 s-1 at 26°C) are in good agreement with literature data for X = ammonia and halide. The activation parameters determined for the reactions are: ΔH≠ = 41 ± 2 kJ mol-1, ΔS≠ = -114 ± 7 J K-1 mol-1 and ΔV≠ = -13.6 ± 0.3 cm3 mol-1 for [Ru(NH3)6]3+; ΔH≠ = 34.4 ± 1.0 kJ mol-1, ΔS≠ = -132 ± 3 J K-1 and ΔV≠ = -18.0 ± 0.5 cm3 mol-1 for [Ru(NH3)5Cl]2+; and ΔH≠ = 31.0 ± 0.7 kJ mol-1 and ΔS≠ = -108 ± 2 J K-1 mol-1 for [Ru(NH3)5(H2O)]3+. Bond formation with the entering nucleophile appears to be substantial in the transition state for the reaction. An associative substitution mechanism coupled to a concerted electron transfer process to produce [RuII(NH3)5- (NO+)]3+ is proposed for all three reactions. Possible reasons for the significantly faster reaction observed in case of the aqua complex are discussed.
Kinetics of reduction of aqueous hexaammineruthenium(III) ion at Pt and Au microelectrodes: Electrolyte, temperature, and pressure effects
Vijaikanth, Vijendran,Li, Guangchun,Swaddle, Thomas W.
, p. 2757 - 2768 (2013/04/10)
Rate constants kel obtained by impedance spectroscopy for the reduction of Ru(NH3)63+ at polycrystalline Pt and Au ultramicroelectrodes depend strongly on the identity and concentration of the anion present in t
