Actinide complexation studies

Nuclear Magnetic Relaxation Studies on Actinide Ions and Models of Actinide Complexes Jean F Desreux... 

NUCLEAR MAGNETIC RELAXATION STUDIES ON ACTINIDE IONS AND MODELS OF ACTINIDE COMPLEXES... 

H20 (40) and CsPr(C03)2 (41). The powder X-ray diffraction technique was used to study most solid carbonates of lanthanides. Lanthanide/actinide complexes, M(C03)2 2re (n = 1 -3) have been... 

Thiocyanate. — On the basis of /-orbital hybridization Diamond [351] predicted the formation of stronger actinide complexes with thiocyanate ion than for the rare earths. Subls and Chopfin [352] have studied the ion exchange behaviour of many actinide and rare earth thiocyanate complexes and have shown that europium is eluted much sooner than americium from Dowex-1 with ammonium thiocyanate. The stability constants for the formation of MSCN2+ and M(SCN)2 complexes for Nd3+, Eus+, Pu3+, Am3+, Cm3+, and Cf34 have been measured [353] and are tabulated in Table 25. It is apparent from the table that the formation... 

Bagnall and Xing-fu205,206 in their study of lanthanide and actinide complexes developed a more sophisticated approach to the analysis of the steric demands of ligands. The emphasis of their work, in contrast to that previously discussed, was on ligands other than phosphines. 

Density functional theory (DFT) has been used extensively for the theoretical study of actinide complexes, making it one of the few first-principles methods that can... 

Relativistic effects cannot be neglected if heavier systems are studied we have discussed the major relativistic effects on calculated NMR shieldings and chemical shifts in this chapter. Besides relativistic effects, electron correlation has to be included for even a qualitatively correct treatment of transition metal or actinide complexes. So far, DFT based methods are about the only approaches that can handle both relativity and correlation, and DFT is, for the time being, the method of choice for these heavy element compounds. In this chapter, we have presented results from two relativistic DFT methods, the Pauli- (QR-) and ZORA approaches. 

Gannaz, B., Antonio, M.A., Chiarizia, R., Hill, C., Cote, G. 2006. Structural study of trivalent lanthanide and actinide complexes formed upon solvent extraction. Journal of the Chemical Society, Dalton Transactions 38 4553-4562. 

Chloride complexation studies of the actinide ions An3+, An4+, An02, and AnO + (An = U, Np, Pu) were reported in several comprehensive reviews [293-295], More recent investigations on aqua and chloro complexes of U02+, NpOz+, Np4+, Pu3+, etc., by x-ray absorption fine structure spectroscopy (XAFS) were reported [296,297]. In particular, it was established for U(IV) and Th(IV) aqua ions and fluoride complexes that both M(IV) aqua ions are 10-coordinate with M — O bond distances for U(IV) and Th(IV) of 2.42 0.01 A and 2.45 0.01 A, respectively [297], Physical and chemical studies of uranium aqueous complexes are reported [298,299a], A series of articles is dedicated to specific sequestering agents for the actinides [299b-e],... 

Novel tetrahydroxamate chelators for Actinide complexation synthesis and binding studies. [A. S. Gopalan, V. J. Huber, O. Zincircioglu, P. H. Smith, J. Chem. Soc., Chem. Commun. 1992, 1266-1268] [ 13]. 

As for the lanthanides, actinide complexes display high coordination numbers. A study of the aqua ions of early actinides makes an interesting comparison (Table 11.1 lists numbers of water molecules and bond lengths). 

Inorganic phosphate ligands are important with respect to the behavior of actinides in the environment and as potential waste forms. There have been a number of experimental studies to determine the equilibrium constants in the actinide-phosphoric acid system, but they have been complicated by the formation of relatively insoluble solid phases and the formation of ternary actinide complexes in solution. 

The actinides have a high degree of specificity for neutral and anionic oxygen-containing organic molecules. The actinide complexes with O -donor ligands that are most widely studied include alkoxides, aryloxides amide, carboxylates, and oxalates. Complexes with alcohols, ethers, esters, ketones, aldehydes, ketoenolates, and carbamates have also been reported. 

---