Complexes in the Ni2+-imidazole-RN(CH2COO-)(2) systems. The crystal structures of tris(imidazole)iminodiacetatonickel(II) monohydrate, hexa(imidazole)nickel(II) bis(N-methyliminodiacetato)nickelate(II) hexahydrate, and tetra(aqua)bis(imidazole)nickel(II) bis(N-benzyliminodiacetato)nickelate(II)

Crystals of different compositions, namely [Ni(Ida)(Im)(3)]. H2O (I), [Ni(I m)(6)][Ni(Mida)(2)]. 6H(2)O (II), and [Ni(Int)(2)(H2O)(4)][Ni(Bida)(2)] (II I), have been precipitated from aqueous solutions of the Ni2+-Lig(2-)-Im sy stems, where Lig(2-) is Ida, Mida, and Bida, respectively. The crystal stru ctures of I-III are determined by Xray diffraction analysis (R = 0.0307, 0. 0348, and 0.0302 for 3061, 4706, and 2882 reflections, respectively). Cryst als I are built of monomeric mixed-ligand complexes and molecules of crysta llization water, which are interlinked by hydrogen bonds into a three-dimen sional framework. In II and III, the ligands Lig(2-) and Im form charged co mplexes separately. In II, the cationic and anionic layers of the complexes alternate along the c-axis. Numerous hydrogen bonds involving molecules of crystallization water link the layers into a three-dimensional framework. In III, the cationic and anionic complexes, which serve as proton donors an d accepters, respectively, are bound into layers parallel to the xy plane. (C) 2000 MAIK "Nauka/Interperiodica".