Electronic effects and trans substitution in octahedral complexes of chromium(III)
Journal Article
·
· Inorg. Chem.; (United States)
- Iowa State Univ., Ames
Kinetics and equilibrium data were determined for the formation of 1:1 adducts of NCS/sup -/ with four complexes of the general formula (H/sub 2/O)/sub 5/CrR/sup 2 +/ (R = CH/sub 2/OH, CH/sub 2/OCH/sub 3/, CH/sub 2/CN, and CH(CH/sub 3/)/sub 2/). The kinetic data for the approach to equilibrium follow the rate law k/sub obsd/ = (A(SCN/sup -/) + B)/(1 + C(SCN/sup -/)) and are consistent with both a limiting S/sub N/1 (or D) and a dissociative ion-pairing (I/sub D/) mechanism. The rate constants of the trans-water exchange in these and two previously studied complexes of the same general type (R = CHLl/sub 2/ and CH/sub 2/Cl) were approximated as a ratio A/C. The correlation of these rate constants and ones for the trans-water exchange in complexes Cr(H/sub 2/O)/sub 5/X/sup 2 +/ (X = I/sup -/, Cl/sup -/, and SCN/sup -/) with the electron-donating ability of the labilizing groups R and X as measured by a Hammett substituent constant was examined. The same correlation was obtained for a limited number of available rate constants for the Cr-NCS bond breaking in the adducts trans-Cr(H/sub 2/0)/sub 4/R(NCS)+, indicating that the trans-labilizing ability of group R does not depend on the nature of the leaving group. The complex (H/sub 2/O)/sub 5/CrCH(CH/sub 3/)/sub 2//sup 2 +/ reacts with SCN/sup -/ more slowly than predicted by this correlation.
- OSTI ID:
- 5226019
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 21:4; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Journal Article
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Wed Jul 29 00:00:00 EDT 1987
· Inorg. Chem.; (United States)
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OSTI ID:5522724
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Journal Article
·
Mon Oct 31 23:00:00 EST 1977
· Inorg. Chem.; (United States)
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OSTI ID:5309241
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Thesis/Dissertation
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Tue Dec 31 23:00:00 EST 1985
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OSTI ID:6855645
Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM COMPLEXES
COMPLEXES
CONFORMATIONAL CHANGES
DATA
DIAGRAMS
DISSOCIATION
ELECTRON TRANSFER
EQUATIONS
EQUILIBRIUM
EXPERIMENTAL DATA
INFORMATION
ION PAIRS
KINETICS
NUMERICAL DATA
OXIDATION
REACTION KINETICS
SCATTERPLOTS
TRANSITION ELEMENT COMPLEXES
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM COMPLEXES
COMPLEXES
CONFORMATIONAL CHANGES
DATA
DIAGRAMS
DISSOCIATION
ELECTRON TRANSFER
EQUATIONS
EQUILIBRIUM
EXPERIMENTAL DATA
INFORMATION
ION PAIRS
KINETICS
NUMERICAL DATA
OXIDATION
REACTION KINETICS
SCATTERPLOTS
TRANSITION ELEMENT COMPLEXES