The spin-transition properties of Fe(III) complexes with hetarylformazan in an ion-exchange polymer: An EPR study

作者：Vishnevskaya G P^*; Frolova E N; Ovchinnikova I V; Pervova I G; Rezinskikh Z G

来源：Russian Journal of Physical Chemistry, 2010, 84(8): 1388-1394.

DOI：10.1134/S0036024410080200

For the first time, the EPR method was used to reveal and study the special features of spin-transition processes between high-spin and low-spin iron(III) complexes with hetarylformazans immobilized on an ion-exchange polymer. An analysis of completely reversible temperature dependences of EPR line positions, widths, and integral intensities in the spectra of high-spin and low-spin complexes allowed four temperature intervals to be identified. These intervals corresponded to preparative periods of spin-transition processes (450-275 K, intervals I and II), their appearance (275-230 K, interval III), and occurrence (230-100 K, interval IV). Local concentrations and spin exchange frequencies in clusters were estimated. Effects related to high-spin complex EPR signal shifts during temperature changes and to the duration of sample storage were revealed. High-spin complexes were found to be very sensitive to external actions, as distinct from very stable low-spin complexes. Experimental EPR observations obtained for ion-exchange polymer satisfied the concept of the nucleation and growth of domains in the spin-transition process.

• 出版日期2010-8