Jump to main content
Jump to site search

Issue 48, 2012
Previous Article Next Article

Supramolecular architectures of novel chromium(III) oxalate complexes: steric effects of the ligand size and building-blocks approach

Author affiliations

Abstract

Five new oxalate complexes of chromium(III), [Hphen][Cr(phen)(C2O4)2]·2H2O (1), [Cr(phen)2(C2O4)][Cr(phen)(C2O4)2]·3H2O (2), [Cr(phen)2(C2O4)]NO3·H2C2O4·H2O (3), [Cr(bpy)2(C2O4)][Cr(bpy)(C2O4)2]·3H2O (4) and [Cr(bpy)2(C2O4)]NO3·1/2H2C2O4·4H2O (5) (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine), were prepared by using an (oxalato)tantalate(V) solution as a source of oxalate ligands. The compounds contain either the discrete mononuclear [Cr(L)2(C2O4)]+ cation [L = phen (3); L = bpy (5)] or the discrete mononuclear [Cr(L)(C2O4)2] anion [L = phen (1)], or both types of mononuclear ions [L = phen (2); L = bpy (4)]. The crystal structures are dominated by the hydrogen-bonding and π⋯π-stacking interactions that give rise to the overall two- (compounds 1, 2, 4, 5) or three-dimensional (compound 3) architectures. Compounds 2 and 4 represent a borderline case between isostructurality and non-isostructurality; they exhibit an analogous packing of the cation and the anion units, but the crystallization water molecules occupy different positions – due to a difference in size between the phen and bpy ligands. The influence of steric factors is evident also in the case of 3 and 5, which, despite very similar chemical formulae, exert a completely different packing of the constituents. By the self-assembling of 1 and 4, used as building blocks in the reaction with calcium(II) cations, the heterobimetallic polymeric compounds {[CaCr2(phen)2(C2O4)4]·5H2O}n (6) and {[CaCr2(bpy)2(C2O4)4]·0.83H2O}n (7) were obtained. The crystal structure of 7 is reported: the [Cr(bpy)(C2O4)2] unit, through the two oxalate groups, acts as a chelating ligand towards Ca cations, resulting in heterometallic one-dimensional double zigzag chains, formed of diamond-shaped units. The characterization of the compounds obtained was accomplished by the spectroscopy and thermal analysis methods.

Graphical abstract: Supramolecular architectures of novel chromium(iii) oxalate complexes: steric effects of the ligand size and building-blocks approach

Back to tab navigation

Supplementary files

Publication details

The article was received on 14 May 2012, accepted on 01 Oct 2012 and first published on 04 Oct 2012


Article type: Paper
DOI: 10.1039/C2DT32249H
Citation: Dalton Trans., 2012,41, 14611-14624
  •   Request permissions

    Supramolecular architectures of novel chromium(III) oxalate complexes: steric effects of the ligand size and building-blocks approach

    L. Androš, M. Jurić, K. Molčanov and P. Planinić, Dalton Trans., 2012, 41, 14611
    DOI: 10.1039/C2DT32249H

Search articles by author

Spotlight

Advertisements