Ligand Effects on the Rate and Mechanism of Solvent Exchange at Rhodium(III) and Iridium(III)

Cusanelli, Antonio; Nicula-Dadci, Lynda; Frey, Urban; Merbach, André E.

doi:10.2533/chimia.1996.618

Cited by 9 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Fitting of this Equation to the (∆A,[L] o ) data led to the equilibrium constant K ϭ k L /k ϪL . Ϫ The volume of activation was obtained from the pressure dependence of k obsd according to Equation (12). A correction for the pressure dependence of the activity coefficients (less than 0.6 cm 3 mol Ϫ1 under the given conditions [42] ) was not applied.…”

Section: Methodsmentioning

confidence: 99%

“…∆V ϶ exptl ϭ ϪRT (Ѩ ln k obsd /ѨP) T (12) Crystallography: The crystals were obtained from aqueous solutions (pH ϭ 2Ϫ3, HClO 4 ) as stated above. Measurements were made with a four-circle diffractometer (STOE-STADI-4) using graphite-monochromated Mo-K α radiation (λ ϭ 0.71069 A ˚); scan 2θ:ω ϭ 1:1.…”

Section: Methodsmentioning

confidence: 99%

“…Ir(1)ϪO(19A) [a] 2.108( 6) O( 19)ϪIr( 1)ϪO( 18) 81.5(3) Ir( 1)ϪN (12) 2.136( 8) N( 12)ϪIr( 1)ϪO( 18) 76.8(4) Ir( 1)ϪO (18) 2.138( 5) O( 19)ϪIr( 1)ϪN( 12) 78.7(3) Ir( 1)ϪC( 6)…”

Section: Distance [A ˚] Atoms Angle [°] Atomsunclassified

See 2 more Smart Citations

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations CpIr(A−B)(H2O)2+/+ in Aqueous Solution (Cp = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Poth

Paulus

Elias

et al. 2001

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

The perchlorate complexes of a series of half‐sandwich monoaqua cations Cp*Ir(A−B)(H2O)2+/+ with A−B = prol (D/L‐proline anion), picac (picolinic acid anion), R,R‐dach [(−)‐(1R,2R)‐1,2‐diaminocyclohexane], R,R‐dpen [(+)‐(1R,2R)‐1,2‐diphenylethylenediamine], phen (o‐phenanthroline), and bpy (2,2′‐bipyridine) (Cp* = η5‐pentamethylcyclopentadienyl anion) have been prepared and characterized. An X‐ray structure analysis of Cp*Ir(R,R‐dach)(H2O)(ClO4)2·H2O has revealed that the cation Cp*Ir(R,R‐dach)(H2O)2+ has a distorted pseudo‐octahedral coordination geometry. In the case of A−B = prol, crystallization from water led to the trinuclear complex [Cp*Ir(D‐prol)]3(ClO4)3, which has also been characterized by X‐ray structure analysis. The experimental data suggest that in aqueous solution the trinuclear proline complex dissociates to form the cation Cp*Ir(D‐prol)(H2O)+. The proton dissociation constants of the coordinated water in Cp*Ir(A−B)(H2O)2+/+ have been determined as pKa = 7.5 (A−B = bpy) and pKa = 7.1 (A−B = R,R‐dach and picac). Substitution of the water in Cp*Ir(A−B)(H2O)2+/+ by the monodentate ligands L = py (pyridine), DMS (dimethyl sulfide), TU (thiourea), and monodentate anions according to the Equation Cp*Ir(A−B)(H2O)2+/+ + L → Cp*Ir(A−B)L2+/+ + H2O has been studied by multi‐wavelength stopped‐flow spectrophotometry in aqueous solution at I = 0.2 M. This kinetic investigation, carried out at different concentrations, temperatures, and pressures, showed that the process obeys second‐order kinetics, where rate = kL[Cp*Ir(A−B)H2O2+/+][L]. The magnitude of the second‐order rate constant kL depends on the nature of both A−B and L. The data for kL have been found to range from 6.4 × 104 M−1s−1 (A−B = D‐prol; L = TU) to 10.5 M−1s−1 (A−B = bpy; L = py) at 298 K. The activation parameters for water substitution at Cp*Ir(A−B)(H2O)2+/+ (A−B = bpy, R,R‐dach, and picac) by L = TU have been evaluated. The activation volumes of ΔV≠ = +2.3, +7.4, and +7.3 cm3 mol−1, respectively, are supportive of an Id mechanism. The results regarding the kinetic lability of the coordinated water in the monoaqua cations Cp*Ir(A−B)(H2O)2+/+ are compared to those obtained for the triaqua cation Cp*Ir(H2O)32+.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations CpIr(A−B)(H2O)2+/+ in Aqueous Solution (Cp = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Poth

Paulus

Elias

et al. 2001

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

show abstract

Oxygen-17 NMR

Gerothanassis¹

2011

Encyclopedia of Magnetic Resonance

View full text Add to dashboard Cite

Iridium

Yellowlees

Macnamara

2003

Comprehensive Coordination Chemistry II

View full text Add to dashboard Cite

Ligand Effects on the Rate and Mechanism of Solvent Exchange at Rhodium(III) and Iridium(III)

Cited by 9 publications

References 0 publications

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations CpIr(A−B)(H2O)2+/+ in Aqueous Solution (Cp = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations CpIr(A−B)(H2O)2+/+ in Aqueous Solution (Cp = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Oxygen-17 NMR

Iridium

Contact Info

Product

Resources

About

Ligand Effects on the Rate and Mechanism of Solvent Exchange at Rhodium(III) and Iridium(III)

Cited by 9 publications

References 0 publications

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations Cp*Ir(A−B)(H2O)2+/+ in Aqueous Solution (Cp* = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations Cp*Ir(A−B)(H2O)2+/+ in Aqueous Solution (Cp* = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Oxygen-17 NMR

Iridium

Contact Info

Product

Resources

About

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations CpIr(A−B)(H2O)2+/+ in Aqueous Solution (Cp = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)

Kinetics and Mechanism of Water Substitution at Half-Sandwich Iridium(III) Aqua Cations CpIr(A−B)(H2O)2+/+ in Aqueous Solution (Cp = η5-Pentamethylcyclopentadienyl Anion; A−B = Bidentate N,N or N,O Ligand)