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Title: Hydrothermal synthesis, structural, Raman, and luminescence studies of Am[M(CN){sub 2}]{sub 3}.3H{sub 2}O and Nd[M(CN){sub 2}]{sub 3}.3H{sub 2}O (M=Ag, Au): Bimetallic coordination polymers containing both trans-plutonium and transition metal elements

Journal Article · · Journal of Solid State Chemistry
 [1];  [2];  [3]
  1. Department of Chemistry, North Carolina A and T State University, Greensboro, NC 27411 (United States)
  2. Department of Chemistry, University of South Alabama, Mobile, AL 36688 (United States)
  3. Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

The polymeric compounds consisting of the man-made element, americium, and gold and silver dicyanides were prepared under mild hydrothermal conditions at 120 deg. C. It was found that the americium ion and the transition metal ions are interconnected through cyanide bridging in the compounds. Given the similarities in the radii of americium and neodymium, crystals of the latter were also characterized for comparison purposes. The four compounds are isostructural and crystallize in the hexagonal space group, P6{sub 3}/mcm, with only slight differences in their unit cell parameters. Crystallographic data (MoK{alpha}, {lambda}=0.71073 A): Am[Ag(CN){sub 2}]{sub 3}.3H{sub 2}O (1), a=6.7205(10) A, c=18.577(3) A, V=726.64(19), Z=2; Am[Au(CN){sub 2}]{sub 3}.3H{sub 2}O (2),a=6.666(2) A, c=18.342(3) A, V=705.9(4), Z=2; Nd[Ag(CN){sub 2}]{sub 3}.3H{sub 2}O (3), a=6.7042(4) A, c=18.6199(14) A, V=724.77(8), Z=2; and Nd[Au(CN){sub 2}]{sub 3}.3H{sub 2}O (4), a=6.6573(13) A, c=18.431(4) A, V=707.2(2), Z=2. The coordination around the Am and/or Nd consists of six N-bound CN{sup -} groups resulting in a trigonal prismatic arrangement. Three capping oxygen atoms of coordinated water molecules complete the tricapped trigonal prismatic coordination environment, providing a total coordination number of nine for the f-elements. Raman spectroscopy, which compliments the structural analyses, reveals that the four compounds display strong signals in the {nu}{sub CN} stretching region. When compared with KAg(CN){sub 2} or KAu(CN){sub 2}, the {nu}{sub CN} stretching frequencies for these compounds blue-shift due to bridging of the dicyanometallate ions with the f-element ions. There is subsequent reduction in electron density at the cyanide center. Compared with the silver systems, the {nu}{sub CN} frequency appears at higher energy in the gold dicyanide complexes. This shift is consistent with the structural data where the carbon-nitrogen bond distance is found to be shorter in the gold dicyanides. - Graphical abstract: Coordination polymeric compounds between the 'man-made' trans-plutonium element, americium, and transition metal ions were prepared using the hydrothermal synthetic procedure. The Am{sup 3+} ion and the transition metals, Au and/or Ag, are interconnected through cyanide bridging. The coordination around americium consists of six CN{sup -} groups coordinated through the N atoms resulting in a trigonal prismatic environment. Three oxygen atoms of coordinated water molecules complete the tricapped trigonal prismatic coordination environment for Am{sup 3+}, providing a total coordination number of 9.

OSTI ID:
21043734
Journal Information:
Journal of Solid State Chemistry, Vol. 180, Issue 11; Other Information: DOI: 10.1016/j.jssc.2007.08.032; PII: S0022-4596(07)00369-6; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
Country of Publication:
United States
Language:
English