Chemical Effects of the (n, γ) Reaction in Chloropentaammine Complexes of Cobalt (IIΙ), Rhodium(III) and Iridium(III)

Abstract

Chloropentaamminecobalt(III) chloride, chloropentaamminerhodium(III) chloride and chloropentaammineiridium (III) chloride labelled with 3e Cl in the cation have been irradiated with thermal neutrons in a flux of 10 11 neutrons cm -2 sec -1 for ten hours. Study of the effects of the (η, γ) reaction has shown that, in the case of the cobalt and rhodium complexes, there is retention of the "CI in the cation, but in the case of the iridium complex about 90% of the Ir-M Cl bonds are broken whilst only one in 10 e iridium atoms are activated. The results are interpreted using a modification to the hot zone theory of HARBOTTLE and SUTIN. An attempt has been made to identify some of the species formed upon dissolution in water. ZusammenfassungIm Kation mit 3e Cl markiertem Chloropentaamminkobalt(III)-chlorid, Chloropentaamminrhodium(III)chlorid und Chloropentaamminiridium(III)chlorid wurden mit thermischen Neutronen in einem Fluß von 10" Neutronen cm~2 sec -1 zehn Stunden lang bestrahlt. Die Untersuchung der Auswirkungen der (n, y)-Reaktion hat gezeigt, daß bei den Kobalt-und Rhodiumkomplexen eine Rückhaltung des 3e Cl im Kation eintritt, während beim Iridiumkomplex rund 90% der Ir-3e ClBindungen zerstört werden, wogegen nur eines von 10® Iridiumatomen aktiviert wird. Zur Interpretation der Ergebnisse dient eine Modifikation von HARBOTTLE und SUTINS Theorie der heißen Zonen. Es ist versucht worden, einige der bei Auflösung in Wasser gebildeten Arten zu identifizieren. ResumeOn a irradie par neutrons thermiques sous un flux de 10" neutrons cm -2 s -1 pendant 10 heures les chlorures de chloropentamminocobalt(III), chloropentamminorhodium(III) et chloropentamminoiridium(III) dont les cations ont ete marques par 3e Cl. L'etude des effets obtenus par reaction (η, γ) a montre que pour les complexes du cobalt et du rhodium il y a une retention de 3e Cl dans le cation, alors que dans le cas du complexe de l'iridium quelques 90% des liaisons Ir-^Cl sont rompues, et seulement un atome sur 10® atomes d'iridium se trouve active. On explique ces resultats par une modification de la theorie de la zone chaude proposee par HARBOTTLE et SUTIN. On a essaye d'identifier quelques-unes des especes qui se sont formees apres dissolution dans l'eau.

Chemical Effects of the (n,y) Reactions in Dichlorotriethylene Tetramine Complexes of Cobalt (111) and Rhodium(lll)

“…This indicates that /?-decay effects are not producing a large change in the breakdown products. This was also shown in earlier work [10] where iridium complexes were studied in comparison with cobalt and rhodium. The cobalt and rhodium complexes had only 0.19 and 0.55 metal atoms activated in every million and even when activation of chlorine, nitrogen and hydrogen atoms are considered, then each (n,y) reaction must break 200,000 to 500,000 metal-chlorine bonds.…”

“…Perchloric acid and potassium Perchlorate were used as support electrolytes. As was observed in our previous paper [10], there are differences between the electrophoretograms of the irradiated materials when carried out in perchloric acid and potassium Perchlorate. The amount of cation observed corresponding to the migration distance of the starting material is higher in perchloric acid.…”

“…Amine complexes of Cobalt (111) in particular, have received much attention, as have some Rhodium (111) and Iridium(lll) amine complexes [10]. HAKBOTTLE [1] found by electrophoretic methods that [Co(NH 3 ) e ](N0 3 ) 3 and [CO(NH 3 ) 5 (N0 3 )](N0 3 ) 2 formed eight and six complex cationic species respectively on irradiation with slow neutrons followed by dissolution in 5% acetic acid.…”

“…Studies have been carried out using optical and geometric isomers of cobalt complexes [7,8,9] to determine the interconversion caused by irradiation but results vary for different complexes. GARDNER et al [10] have recently studied the (n,y) reaction in [Co(NH 3 ) 5 Cl]Cl 2 in which both M C1 and eo Co were used as tracers. Less work has been done on Rhodium and Iridium complexes.…”

“…SCHMIDT [16] has investigated the (n,y) reaction in [Ir(NH 3 ) 6 Cl]Cl 2 and [Rh(NH 3 ) 5 Br](N0 3 ) 2 . GARDNER et al [10] have studied the (n,y) reaction in [Ir(NH 3 ) 5 Cl]Cl 2 and [Rh(NH 3 ) 5 Cl]Cl 2 using »CI labelling of the chlorine atom inside and outside the complexes. Both SCHMIDT and GARDNER found a number of cationic and neutral species for the Iridium complex.…”