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Unexpected Coordination Modes of Bisphosphoramides with Lanthanum(III) and Thorium(IV) Salts: Synthesis, Structural Characterization, Stability, and Extraction Studies
Author(s) -
Goud E. Veerashekhar,
Vijai Anand A. S.,
Pallepogu Raghavaiah,
Brahmmananda Rao C. V. S.,
Nagarajan Sivaraman,
Sivaramakrishna Akella
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202004516
Subject(s) - chemistry , lanthanum , phosphonate , thorium , phosphine oxide , ethylenediamine , reagent , chelation , metal , medicinal chemistry , coordination sphere , crystal structure , nitric acid , phosphine , inorganic chemistry , stereochemistry , crystallography , organic chemistry , uranium , catalysis , materials science , metallurgy
A series of bisphosphoramides of the type R 2 P(O)NHCH 2 CH 2 NHP(O)R 2 ( L ) (where R= n ‐butyl, n ‐hexyl, n ‐octyl, ethoxy, phenyl) is synthesized in two‐steps by Atherton‐Todd reaction of ethylenediamine and H ‐phosphonate derived from the reaction of diethylphosphite and the Grignard reagent. These ligands were employed in the preparation of La(III) and Th(IV)complexes of the general type [LaCl 3 ( L ) 2 ] n and [Th(NO 3 ) 4 Th(IV) 2 ]. Notably, La(III) complexes of bisphosphoramides are found as infinite coordination polymers with bridging phosphine oxide ligands in an intermolecular fashion. In contrast, Th(IV) complexes are formed with two chelating bisphosphoramide ligands around the metal center intramolecularly. All these ligands and the corresponding metal complexes are characterized by spectroscopic and analytical data. The single‐crystal X‐ray analyses of lanthanum and thorium complexes each confirm the coordination modes. Further, these ligands were evaluated to check the extraction behavior with Am(III), U(VI), Th(IV), and Pu(IV) as a function of nitric acid concentration.