Series of trinuclear NiIILnIIINiII complexes derived from 2,6-di(acetoacetyl)pyridine: Synthesis, structure, and magnetism

Takuya Shiga, Nobuhiro Ito, Akiko Hidaka, Hisashi Okawa, Susumu Kitagawa, Masaaki Ohba

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Abstract

Eighteen trinuclear NiII2LnIII complexes of 2,6-di(acetoacetyl)pyridine (H2L) (Ln = La-Lu except for Pm) were prepared by a "one-pot reaction" of H2L, Ni(NO 3)2·6H2O, and Ln(NO3) 3·nH2O in methanol. X-ray crystallographic studies indicate that two L2- ligands sandwich two NiII ions with the terminal 1,3-diketonate sites and one LnIII ion with the central 2,6-diacylpyridine site, forming the trinuclear [Ni2Ln(L) 2] core of a linear NiLnNi structure. The terminal Ni assumes a six-coordinate geometry together with methanol or water molecules, and the central Ln assumes a 10-coordinate geometry together with two or three nitrate ions. The [Ni2Ln(L)2] core is essentially coplanar for large Ln ions (La, Ce, Pr, Nd) but shows a distortion with respect to the two L2- ligands for smaller Ln ions. Magnetic studies for the Ni 2Ln complexes of diamagnetic LaIII and LuIII indicate an antiferromagnetic interaction between the terminal NiII ions. A magnetic analysis of the Ni2Gd complex based on the isotropic Heisenberg model indicates a ferromagnetic interaction between the adjacent NiII and GdIII ions and an antiferromagnetic interaction between the terminal NiII ions. The magnetic properties of other Ni2Ln complexes were studied on the basis of a numerical approach with the Ni2La complex and analogous Zn2Ln complexes, and they indicated that the NiIILnIII interaction is weakly antiferromagnetic for Ln = Ce, Pr, and Nd and ferromagnetic for Ln = Gd, Tb, Dy, Ho, and Er.

Original languageEnglish
Pages (from-to)3492-3501
Number of pages10
JournalInorganic chemistry
Volume46
Issue number9
DOIs
Publication statusPublished - Apr 30 2007
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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