Macrocyclic ligands for uranium complexation. Final report, August 1, 1986--March 31, 1993
Macrocycles, designed for complexation of the uranyl ion by computer modeling studies and utilizing six ligating atoms in the equatorial plane of the uranyl ions, have been prepared and their complexation of the uranyl ions evaluated. The ligating atoms, either oxygen or sulfur, were part of acylurea, biuret or thiobiuret subunits with alkane chains or pyridine units completing the macrocyclic periphery. These macrocycles with only partial preorganization formed uranyl complexes in solution but no crystalline complexes were isolated. Refinement of the cavity diameter by variation of the peripheral functional groups is currently studied to achieve an optimized cavity diameter of 4.7--5.2 {angstrom}. Acyclic ligands containing the same ligating atoms in equivalent functional entities were found to form a crystalline 1:1 uranyl-ligand complex (stability constant log K = 10.7) whose structure was established by X-ray data. This complex underwent a facile, DMSO-induced rearrangement to a 2:1 uranyl-ligand complex whose structure was also established by X-ray data. The intermediates to the macrocycles all behaved as excellent ligands for the complexation of transition metals. Acylthiourea complexes of copper and nickel as well as intermolecular, binuclear copper and nickel complexes of bidentate carbonyl thioureas formed readily and their structures were established in several representative instances by X-ray structural determinations. Tetradentate bis(carbonylthioureas) were found to be very efficient selective reagents for the complexation of copper in the presence of nickel ions. Several preorganized macrocycles were also prepared but in most instances these macrocycles underwent ring-opening under complexation conditions.
- Research Organization:
- Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- FG02-86ER13583
- OSTI ID:
- 486076
- Report Number(s):
- DOE/ER/13583-T1; ON: DE97007699; TRN: 97:011292
- Resource Relation:
- Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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Macrocyclic ligands for uranium complexation
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