Allen J. Weiss

1,1′-Trimethylenetitanocene dichloride and the corresponding compounds of zirconium and hafnium☆

Abstract The preparation and properties of trimethylene bridged titanocene, zirconocene, and hafnocene dichlorides are described. Additional evidence is presented of correlation between ring-ring angles and differential ring-proton shifts in the PMR spectra.

Bridged Ferrocenes. I

Abstract Previously reported correlations between Mossbauer spectra and the number of bridges in trimethylene bridged ferrocene derivatives have now been observed in the electrode potentials and in the electronic spectra. Crystallographic results reported in the subsequent papers of this series are employed to confirm the previous attribution of these effects to ring—ring tilting, iron-to-ring distance, and to a lesser extent the non-planarity of the rings in some compounds. Rearrangement during the bridging reaction is proposed to explain the failure of the formation of the four-bridged compound.

Bridged ferrocenes. VI. Hydrogenation with Pd/C catalyst

Abstract The method of Van Meurs et al. [1] for hydrogenation of ferrocene has been extended to include a variety of bridged ferrocenes. Singly bridged and dibridged ferrocenes containing tri-, tetra-, or pentamethylene bridges were hydrogenated to the corresponding polycyclic hydrocarbons. Conditions required were consistent with a mechanism that involves an initial protonation of the iron atom. Bridge opening to a propylferrocene derivative was observed for the compound with three not-all adjacent trimethylene bridges, and no hydrogenation reaction was observed for the corresponding derivative with tetramethylene bridges. Without catalyst or hydrogen, trifluoroacetylation and a rearrangement of a bridge were observed in the tris(trimethylene) compound. In the presence of catalyst but no hydrogen, an alpha alcohol and the corresponding diferrocenyl ether were obtained. Possible mechanisms are suggested for these reactions.

Szilard--Chalmers reactions in bridged ferrocene derivatives

Abstract Retentions following ( n , γ) reactions in solid state and in solutions in hexane, benzene and dimethylsulfoxide were measured for ferrocene and for four trimethylene bridged derivatives of ferrocene. The retentions decreased with an increase in the number of bridges, differed for isomers containing the same number of bridges, and decreased with increasing polarity of the solvent. A possible intrinsic retention was measured in DMSO, the most polar solvent. All of these results are explained on the basis of ease of the recoiling iron atom to recombine with the organic residue depending on the molecular structure of the residue and on the basis of competition between the solvent and the residue for the iron atom.

Irradiation effects in the storage and disposal of radioactive ion-exchange resins

Research is under way to characterize the effects of self-irradiation on radwastes which may be generated when organic ion-exchange media are used in water demineralization or decontamination operations at nuclear facilities. External factors affecting the relation between laboratory evaluations and field performance are emphasized. Initial experiments do not yet indicate substantial radiation dose-rate effects on radiolytic gas yields or acid product formation, when (fully swollen) sulfonic acid resins are irradiated in a sealed air environment. At the same time, oxygen gas is removed from the environment of irradiated resins. Interaction between mild steel coupons and acidic species produced in the irradiation induced decomposition of sulfonic acid resin results in irradiation enhanced corrosion. Corrosion rates depend on radiation dose rate, moisture content and resin chemical loading. In some cases, corrosion rates decrease with time, suggesting depletion of acidic species within the resin bed, or a synergistic interaction between resin and corrosion coupon. Implications of these and other results on evaluating field behavior of radwaste containing ion-exchange media are discussed. 4 figures, 2 tables.

Szilard-Chalmers reactions of bridged derivatives of titanocene dichloride, zirconocene dichloride and hafnocene dichloride☆

Abstract Retentions following ( n , γ ) reactions in solid state and in solution in benzene were measured for 1,1′-trimethylenetitanocene dichloride and for the corresponding derivatives of zirconocene dichloride and hafnocence dichloride. Comparisons are made of these retentions with those previously measured for the parent compounds. Retentions in solution are best interpreted as due to a fast three-body recombination reaction for the parent compounds and to a fast two-body recombination reaction for the bridged derivatives.