Hydrated neodymium(III) and europium(III) picrate complexes with pyrazine-N-oxide

Compounds with composition Ln(pic)(3). 2pyzNO . 7H(2)O (Ln=Nd, Eu; pic=picr ate; pyzNO=pyrazine-N-oxide) were obtained by reaction of the hydrated lant hanide picrate with pyrazine-N-oxide in ethanol (molar ratio 1:4). The addu cts were characterized by elemental analyses and IR spectra. X-ray single c rystal data for the neodymium complex indicate that the crystal system is t riclinic, space group P (1) over bar. Nd unit cell dimensions are: a=7.930( 1) Angstrom; b=12.869(1) Angstrom; c=20.833(1) Angstrom; alpha=106.414(7) A ngstrom; beta=92.574(7) Angstrom; gamma=92.202(9) Angstrom; V=2034.4(3) Ang strom; Z=2. Europium cell parameter are a=7.882(1) Angstrom, b=12.880(1) An gstrom, c=20.788(2) Angstrom, alpha = 106.224(8)degrees, beta=92.055(7)degr ees, gamma=93.140(7)degrees. One picrate is bidentate, coordinated through the phenoxo oxygen and one oxygen of an o-nitro group and two are not coord inated. One pyrazine-N-oxide is bonded through the oxygen and the other is out of sphere. Six water molecules are bonded and a seventh is not coordina ted. The coordination polyhedron is a distorted tricapped trigonal prism. ( C) 2000 Elsevier Science S.A. All rights reserved.