6533b7cefe1ef96bd1257987

RESEARCH PRODUCT

Uranyl ion complexes with aminoalcoholbis(phenolate) [O,N,O,O′] donor ligands

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Abstract The reaction between uranyl nitrate hexahydrate and phenolic ligand precursor N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-2-aminoethanol (H3L1) in acetonitrile without base affords the dinuclear uranyl complex [(UO2)2(H2L1)2(NO3)2] (1); in the presence of base, the mononuclear complex [UO2(H2L1)2] · 2H2O (2) is formed. Ligand N,N-bis(2-hydroxy-5-t-butyl-3-methylbenzyl)-2-aminoethanol (H3L2) affords a uranyl complex of formula [UO2(H2L2)2] · 2CH3CN (3); ligand N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-3-amino-1-propanol (H3L3) affords a uranyl complex of formula [UO2(H2L3)2] (4); whilst ligand N,N-bis(2-hydroxy-5-t-butyl-3-methylbenzyl)-3-amino-1-propanol (H3L4), used as the hydrochloride, affords a uranyl complex of formula [UO2(H2L4)2] (5). A solid complex with uranyl ion could not be formed using the ligand N,N-bis(2-hydroxy-3,5-di-t-butylbenzyl)-2-aminoethanol. The molecular structures of 1–5 were verified by X-ray crystallography whereby it was ascertained that 1 is a dialkoxo-bridged dinuclear uranyl complex with a U to L ratio of 1:1. The other complexes 2–5 form in a molar ratio of 1:2 (U to L) and bear similar mononuclear, distorted octahedral uranyl structures with the four coordinating phenoxo ligands forming an equatorial plane and resulting in a centrosymmetric structure for the uranyl ion.