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Abstract : |
Two copper(II)-ACC complexes were prepared and characterized: [Cu(bpy)(ACC)(H2O)]أƒآ¢أ‚‹أ‚…CO4 (1) and [Cu(ACC)2]3أƒآ¢أ‚‹أ‚…4H2O (2). Their crystallographic structures are described and analyzed. Spectroscopic characterizations (UV-visible and EPR) confirm that the structure is maintained in solution. These complexes are able to produce ethylene in the presence of hydrogen peroxide in an أƒآ¢أ‚€أ‚إ“ACC Oxidase-likeأƒآ¢أ‚€أ‚آ‌ reaction in water and in methanol. The conversion of ACC into ethylene depends on the amount of base, and, in methanol, 3 equivalents of NaOH are needed for optimum activity. The base is proposed to play a role in H2O2 deprotonation. The presence of an exogenic ligand (bpy) is important for the reactivity and may stabilize a reaction intermediate. Indeed, a brown intermediate with an absorption band centered at 433 nm can be detected at low temperature when 1 is treated with 10 equivalents of H2O2., |
