The recoid feature of central metal atoms in the bi-component solid system of water-soluble metalloporphyrin ion associates
was investigated in bremsstrahlung and thermal neutron irradiation at very low temperatures. Very preferable substitution
of stable Zn central metal atoms by the Cu* recoil was observed in the system of [M(TMPyP)][M′(TCPP)] (M,M′=Cu, Zn) in both irradiations, while no such tendency was
seen in the system of [M(TMPyP)][M′(TPPS)] (M,M′=Cu, Zn). The predominant factor for the difference of the recoil feature
is discussed. (H2TMPyP: tetrakis(4-N-methylpyridyl)-porphine, H2TCPP: tetra(p-carboxyphenyl)porphine, H2TPPS: tetra(p-sulfophenyl)-porphine).
Copper phthalocyanine ( and forms) in neat solid or in dissolved state in conc. H2SO4 was neutron-irradiated, and retention values of64Cu and66Cu were estimated to study whether or not there is any isotope effect in retention between these two (n, )-produced radionuclides. The data show that there is an isotope effect expressed by the ratio of retention of66Cu to that of64Cu, ranged from 1.29±0.12 for form dissolved in conc. H2SO4 to 1.09±0.02 for form in neat solid irradiation. This result coincides with the tendency anticipated from the recoil energy spectra which were computed by a program using Monte-Carlo method.
The retentions of cobalt, copper and zinc recoils were studied in the mixed crystal system of -cobalt phthalocyanine and -zinc phthalocyanine. It was suggested that a part of the retentions of cobalt and zinc recoils was due to a competitive process. The relationship between the retentions of the zinc recoils and their recoil energy in different matrices was discussed.
Authors:H. Shoji, Y. Maruyama, K. Ogawa, Y. Oki, and N. Ikeda
A series of metal -diketonates were irradiated with bremsstrahlung of maximum energy of 50 MeV and the recoil behavior of7Be, formed from12C of ligands through12C(, n)7Be reaction, was investigated.7Be nuclides thus formed were detected partially as central metal atoms of the complexes. Complex yields of7Be were compared and an anomalously high yield was observed in tris-acetylacetonatocobalt(III) [Co(acac)3].
The chemical effect of7Be recoils formed through a12C/, n/7Be process from ligand carbon atoms was investigated in a several phthalocyanines. It was found that7Be-phthalocyanine was synthesized by7Be recoil. Net radiochemical yields of7Be-phthalocyanine were estimated to be 10–20% for copper and zinc phthalocyanines, while for metal-free phthalocyanines, yields above 90% were obtained.
Authors:Y. Kobayashi, Y. Tsuruoka, M. Kubo, H. Nonaka, Y. Yamada, Y. Sakai, H. Shoji, W. Sato, A. Shinohara, Y. Watanabe, and H. Matsue
In order to investigate the physical and chemical effects of neutron capture reaction, a neutron in-beam Mössbauer spectroscopic
study on two isomorphs of iron disulfide: pyrite and marcasite, were carried out with a parallel plate avalanche counter at
room temperature. In both compounds only two major products accounted for the obtained spectrum: one with Mössbauer parameters
close to the parent compound and the other one considered to be a new product. The yield of the parent-like species was different
in the two isomorphs.