Jump to main content
Jump to site search

Issue 1, 2011
Previous Article Next Article

Unsymmetrical diimine complexes of iron(II) and manganese(II): synthesis, structure and photoluminescence of an isomer

Author affiliations

Abstract

Two bis(unsymmetrical diimine) complexes of (LNO2ϕ1)(LNO2ϕ2)MIICl2 family with M = Fe and Mn, are reported (LNO2ϕ = (E)-3-nitro-N-(pyridine-2-ylmethylene)aniline; ϕ = dihedral angle between the diimine unit including pyridine ring and the phenyl ring planes). Pure tcc-(LNO233.6)(LNO279.3)FeIICl2·0.5H2O (1) and tcc-(LNO232.0)(LNO279.4)MnIICl2·0.5H2O (2) isomers have been successfully isolated in high yields and characterized by elemental analyses, variable temperature magnetic susceptibility measurements, IR, mass, UV-vis and Mössbauer spectra including the single-crystal X-ray structure determinations that identified strong intermolecular non-bonding interactions in lattice (tcc refers to transciscis positions with respect to pyridine N-imine N–Cl donors). Geometries optimizations of all possible tcc, ttt, ctc, ccc and cct isomers of iron at the B3LYP/DFT level in gas-phase have shown that the tcc-isomer incorporating two non-equivalent ligands as in (LNO242)(LNO261)FeIICl2, 1 (g), is stabilized by 6–20 kJ mol−1 compared to other isomers where two ligands are equivalent. The frozen methanol glasses of 1 and 2 are luminescent at 77 K (1: λext = 370, λem = 521 nm, χ2 = 1.3, τavg = 0.57 ns; 2: λext = 368, λem = 524 nm, χ2 = 1.1, τavg = 0.90 ns). The DFT calculations have identified four closely spaced localized π* orbitals comprising of two non-equivalent ligands as UPMOs. The features contrast the tcc-isomer of (Lϕ)2FeIICl2 (3), congener of 1 without –NO2 substitution and non-emissive (bpy)2FeIICl2 (4) where two ligands are equivalent. TD-DFT calculations have assigned intra-ligand (IL) and ligand to ligand charge transfer (LLCT) dominated excited states as the origin of luminescence of 1 and 2.

Graphical abstract: Unsymmetrical diimine complexes of iron(ii) and manganese(ii): synthesis, structure and photoluminescence of an isomer

Back to tab navigation

Supplementary files

Publication details

The article was received on 21 Jul 2010, accepted on 27 Sep 2010 and first published on 11 Nov 2010


Article type: Paper
DOI: 10.1039/C0DT00883D
Citation: Dalton Trans., 2011,40, 146-155
  •   Request permissions

    Unsymmetrical diimine complexes of iron(II) and manganese(II): synthesis, structure and photoluminescence of an isomer

    A. S. Roy, M. K. Biswas, T. Weyhermüller and P. Ghosh, Dalton Trans., 2011, 40, 146
    DOI: 10.1039/C0DT00883D

Search articles by author

Spotlight

Advertisements