Linear free‐energy relationships in semiquinone species and their Mn(II) and Cu(II) complexes |
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| Authors: | Joseph C Sloop David A Shultz Mithra Beikmohamadi Marcus Benjamin Shepler |
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| Institution: | 1. (678) 407–5022;2. School of Science and Technology, Georgia Gwinnett College, , Lawrenceville, GA, 30043 USA;3. Department of Chemistry, North Carolina State University, , Raleigh, NC, 27695 USA;4. Department of Chemistry, University of St. Thomas, , St. Paul, MN, 55105 USA |
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| Abstract: | Linear free‐energy relationships for a series of functionalized semiquinone ligands and their MnII‐ and CuIIhydro‐tris(3‐cumenyl‐5‐methylpyrazolyl) borate complexes were examined. Quinone–semiquinone cycle half‐wave reduction potentials and semiquinone hydrogen hyperfine coupling constants (aH) were determined and their correlation with Hammett σ parameters reported. A new σ parameter, σaH, has been proposed. MnII and CuII metal complex metal–ligand charge transfer and n → π* UV transitions were found to be modulated by substituents. Satisfactory Hammett correlations between UV transitions and various σ values have been determined and compared in a number of instances. Copyright © 2011 John Wiley & Sons, Ltd. |
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| Keywords: | Hammett correlation hydro‐tris(3‐cumenyl‐5‐methylpyrazolyl)borate hyperfine coupling semiquinone |
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