High-pressure EPR spectroscopy: paramagnetic exchange of organic radicals with iron (III) acetylacetonate

作者：Hussain Tajamal; Rasmussen Kenneth^*; Kokorin Alexander I; Grampp Guenter

来源：Molecular Physics, 2013, 111(18-19): 2717-2722.

DOI：10.1080/00268976.2013.788744

• electron paramagnetic resonance
• paramagnetic exchange
• diffusion
• high-pressure chemistry

In this work the spin exchange between organic radicals and a paramagnetic transition metal complex is studied as a function of pressure. Spin exchange rate constants of the tetracyanoethene radical anion (TCNE center dot-) and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) with iron (III) acetylacetonate (Fe(acac)(3)) were measured at elevated pressures with the help of electron paramagnetic resonance (EPR) spectroscopy. As the reactions are diffusion controlled, the effect of pressure on the paramagnetic exchange is examined by comparison of experimental rate constants, determined from line-broadening experiments, with the corresponding theoretical ones. The activation volumes of the reactions were between 4 and 8mol(-1) cm(3), consistent with results reported in literature.

• 出版日期2013-10-1