RADIATION-DAMAGE IN PT(II) COMPLEXES - EPR STUDY OF AN X-IRRADIATED SINGLE-CRYSTAL OF HYL-IMIDAZOLINE-2-THIONE)(4)CL(2-CENTER-DOT)4H(2)O

Several radiation defects have been detected by EPR in a single-crysta l of Pt(dmimt)(4)Cl-2.4H(2)O (dmimt = 1,3-dimethyl-imidazoline-2-thion e). In order to identify these radiogenic species, the structure of th e crystal has been resolved and the angular dependence of the EPR sign als has been analysed. The resulting g tensors and Pt-195 hyperfine te nsors have been determined and the orientations of their principal axe s have been compared to those of the bond directions of the precursor. It is shown that both Pt(I) and Pt(III) complexes are trapped, wherea s Pd(dmimt)(4)(2+) present as an impurity, leads only to the Pd(I) spe cies. The temperature dependence of the EPR spectra gives information about the relative stability of the paramagnetic species and shows tha t the formation of some species, especially the Pt(III) complexes, req uires drastic modifications of the parent Pt(II) cation. (C) 1997 Else vier Science Ltd.