Radiation-induced degradation of (Ph)3GeMn(CO)5 studied by EXAFS spectroscopy

The atomic structure degradation of (Ph)3GeMn(CO)5 resulting from radiolysis was studied by EXAFS spectroscopy. Mn and Ge K-edge EXAFS of (Ph)3GeMn(CO)5 were measured in the radiation dose range from 6.0x106 to 2.1x107 J/m2. The following stages of structure degradation were found as functions of accumulated dose at radiation fluxes. At lower doses of 6x106-8x106 J/m2 Mn-Ge bonds decompositions were detected: as a result the complex splits into fragments [(Ph)3Ge] and [Mn(CO)n]. At radiation dose 7.8x106 J/m2 the [Mn(CO)n] fragment partially loses CO-ligands to form Mn-Mn bonds, which are typical of Mn dimer. Further increase of the radiation dose up to 1.3x107 J/m2 results in formation of Mn nanoparticles interacting with ligand environment. These Mn-nanoparticles are not changed at further increasing of radiation dose. The fragment [(Ph)3Ge] remains unchanged up to 1.3x107 J/m2. In the radiation dose range from 1.3x107 to 2.1x107 J/m2, the [(Ph)3Ge] fragment loses the Ph-ligands to form Ge-Ge bonds. The final products of radiolysis are inhomogeneous metal nanoparticles