34788-74-4Relevant articles and documents
Kochi, J. K.,Rust, F. F.
, p. 2017 - 2018 (1961)
Kinetics of heterolysis of pentaaquachromium(III) complexes of benzyl and 4-methyl-, cyano-, and fluoro-substituted benzyl ligands
Zhang, Zhongsheng,Jordan
, p. 5472 - 5476 (2008/10/08)
The kinetics of the heterolysis have been studied for (H2O)5Cr-CH2C6H5 2+ and the 2-, 3-, and 4-cyano derivatives; the 4-fluoro and 2,4- and 3,5-difluoro derivatives, and the 4-CH3 complex. The reactions were studied in the general temperature range 60-75°C in 0.01-0.95 M HClO4 at an ionic strength of 1.00 M (NaClO4/HClO4). Chromium(II) was added to suppress homolysis. The reaction rate has terms first order and independent of [H+] and pathways involving catalysis by sulfate ion have been characterized for all but the more reactive 2- and 4-cyano systems. The latter is the most reactive (studied at 25-43°C) and is also unusual in showing a saturation effect with [H+] which is attributed to protonation of the ligand to give (H2O)5Cr-CH2C6H 4(4-CNH)3+ with pKa = 1.50 (25°C, 1.00 M NaClO4/HClO4). The results are discussed in terms of substituent effects on the general reactivity and the activation parameters, ΔH* and ΔS*.
Kinetic study of the modes of decomposition of pentaaquabenzylchromium(III)
Kita,Jordan
, p. 3489 - 3494 (2008/10/08)
The preparation of moderately concentrated solutions of (H2O)5CrCH2C6H5 2+ has allowed its visible spectrum to be fully characterized with maxima (nm (molar absorptivities, M-1 cm-1)) at 533 (31.9) and 358 (2.15 × 103). The kinetics of acidolysis of (H2O)5CrCH2C6H5 2+ have been studied between 56 and 74°C in 1 M NaClO4/HClO4 and in the presence of chromium(II) to suppress homolysis. The rate law has terms independent of (k0) and first order in [H+] (ka) with ΔH0* and ΔHa* values (kcal mol-1) of 21.4 ± 0.4 and 20.3 ± 2.1 and ΔS0* and ΔSa* values (cal mol-1 deg-1) of -11.7 ± 1.9 and -16.5 ± 8.7. Calculated values at 25°C are k0 = 3.8 × 10-6 s-1 and ka = 2.0 × 10-6 M-1 s-1. The homolysis reaction was studied at 41°C and found to have apparent half-order kinetics in [(H2O)5CrCH2C6H5 2+] with an inverse dependence on the hydrogen ion concentration. The products for the heterolysis, homolysis, and decomposition in the presence of ethanol and dioxygen have been characterized by ion-exchange separation and spectrophotometry for the inorganic species and by extraction and proton NMR spectroscopy for the organic products.
