Solvent exchange kinetic parameters

Frank and Wen [Fr 57] and later Caldin and Bennetto [Be 71, Ca 73] looked for a correlation between the solvent-exchange kinetic parameters for divalent metal ions and the structural properties of the solvent. Tanaka [Ta 76] demonstrated a... 

This methodology is especially useful for labile paramagnetic systems, and many of the solvent-exchange kinetic parameters given in Tables 3.13 and 3.18 have been determined by this method. A further application is discussed in Section 4.1.2 and described in Figure 4.2. 

Solvent Exchange.—Kinetic parameters for water exchange at some d and d complexes of formula [ML5(OH2)] + are given in Table 21. A comparison of... 

A variety of geometries have been established with Co(II). The interconversion of tetrahedral and octahedral species has been studied in nonaqueous solution (Sec. 7.2.4). The low spin, high spin equilibrium observed in a small number of cobalt(Il) complexes is rapidly attained (relaxation times < ns) (Sec. 7.3). The six-coordinated solvated cobalt(ll) species has been established in a number of solvents and kinetic parameters for solvent(S) exchange with Co(S)6 indicate an mechanism (Tables 4.1-4.4). The volumes of activation for Co " complexing with a variety of neutral ligands in aqueous solution are in the range h-4 to + 1 cm mol, reemphasizing an mechanism. 

Solvent Effects. Kinetic parameters for the reaction of [Pt(dien)Br]+ with 3-cyanopyridine have been determined in deuterium oxide solution, in order to make a comparison of reactivities in deuterium oxide and in ordinary water. To avoid any complications from protium-deuterium exchange between solvent and co-ordinated ligand, the perdeuterio-diethylenetriamine complex was used as substrate in deuterium oxide solvent. The kinetic parameters are compared in Table 1. The results were discussed in terms of an associative mechanism and the smaller solvating effects of D2O compared with HgO. ... 

How might one measure the kinetic parameters for the self-exchange k 10 M s ) of (T -arene)2CrV(Ti -tu ene)2Cr in solution What would be the advantages of such a system for testing outer-sphere electron transfer theories How might the rate constant vary with the optical and static dielectric constants for various solvents ... 

An essential step in the homogeneous catalyzed water gas shift reaction involves nucleophilic attack of hydroxide ion at the carbon atom of a metal-bound CO, with a subsequent process leading to the extrusion of COu These two processes have been studied for the reaction of oxygen-18 enriched NaOH with Cr(CO)e in a biphasic medium in the presence of a phase-transfer catalyst. Oxygen exchange was observed to occur at a faster rate than metal hydride, fi-H[Cr(CO)s]2, formation with concomitant production of C02- The kinetic parameters for the reaction of fji-H[Cr(CO)5]2 with CO in alcoholic solvent to afford Cr(CO)e and H2 have been determined. 

The rate of exchange of bonded water with bulk solvent gives evidence that the process is associative, that is, it occurs through a seven-coordinate intermediate. The two reported determinations give (averaged) kinetic parameters of k, = 2.15 x 10 s = 7.8kcal mole ... 

Theory. The relationship of the chemical aspects of complexatlon reactions to the performance of facilitated transport membranes Is discussed by Koval and Reyes (108). They describe a procedure which can be used to predict and optimize the facilitated transport of gases, Including measurement of the appropriate equilibrium, transport, and kinetic parameters and structural modification of the carrier to Improve the performance of the membrane. Examples of this procedure and carrier modification are given for derivatives of Fe(II) tetralmlne complexes which reversibly bind CO In nitrile solvents (118). Experimental challenges In the measurement of the appropriate properties for other membrane configurations such as reactive Ion exchange membranes and reactive polymer membranes are also discussed. 

Kinetic parameters for solvent exchange at hexasolventoruthenium(II) and -(III) are compared with a selection of analogous data for hexasolventoiron species in Table The results suggest that solvent exchange at [Ru(NCMe)6], ... 

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