title: Structural study on 2,2'-(methylimino)bis(N,N-dioctylacetamide) complex with Re(VII)O4- and Tc(VII)O4- by 1H NMR, EXAFS, and IR spectroscopy.
abstract: The structures of the complex of 2,2'-(methylimino)bis(N,N-dioctylacetamide) (MIDOA) with M(VII)O(4)(-) (M = Re and Tc), which were prepared by liquid-liquid solvent extraction, were investigated by using (1)H nuclear magnetic resonance (NMR), extended X-ray absorption fine structure (EXAFS), and infrared (IR) spectroscopy. The (1)H NMR spectra of the complex of MIDOA with Re(VII)O(4)(-) prepared in the organic solution suggest the transfer of a proton from aqueous to organic solution and the formation of the H(+)MIDOA ion. The EXAFS spectra of the complexes of H(+)MIDOA with Re(VII)O(4)(-) and Tc(VII)O(4)(-) show only the M-O coordination of the aquo complexes, suggesting that the chemical state of M(VII)O(4)(-) was unchanged during the extraction process. The results from (1)H NMR and EXAFS, therefore, provide evidence of M(VII)O(4)(-)···H(+)MIDOA complex formation in the organic solution. The IR spectra of Re(VII)O(4)(-)···H(+)MIDOA and Tc(VII)O(4)(-)···H(+)MIDOA were analyzed based on the structures and the IR spectra that were calculated at the B3LYP/cc-pVDZ level. Comparison of the observed and calculated IR spectra demonstrates that an intramolecular hydrogen bond is formed in H(+)MIDOA, and the M(VII)O(4)(-) ion interacts with H(+)MIDOA through multiple C-H(n)···O hydrogen bonds.
authors.affiliation: Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan. saeki.morihisa@jaea.go.jp
authors.forename: Morihisa
authors.initials: M
authors.lastname: Saeki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Ayaka
authors.initials: A
authors.lastname: Nakai
authors.forename: Akira
authors.initials: A
authors.lastname: Ohashi
authors.forename: Dipanjan
authors.initials: D
authors.lastname: Banerjee
authors.forename: Andreas C
authors.initials: AC
authors.lastname: Scheinost
authors.forename: Harald
authors.initials: H
authors.lastname: Foerstendorf