Impact of ferrocenyl and pyridyl groups attached to dithiocarbamate moieties on crystal structures and luminescent characteristics of group 12 metal complexes

• Five new Zn(II), Cd(II) and Hg(II), monomeric (5), dimeric (1, 4) and 2-D polymeric (2, 3) dithiocarbamate complexes were synthesized and characterised.
• Their crystal structures have been assessed by DFT calculations. The supramolecular structure have been sustained by CH … π (MS2C, chelate) interactions.
• Solid phase photoluminescent properties have been studied.

Metal-directed self assembly of ferrocenyl based pyridyl functionalized dithiocarbamates afforded the novel macrocyclic metal-organic coordination polymers, [M(L)2]∞ (M = Zn(II), L = L2 (N-ferrocenylmethyl-N-pyridin-4-ylmethyl) dithiocarbamate 2, M = Cd(II), L = L1 (N-ferrocenylmethyl-N-pyridin-3-ylmethyl) dithiocarbamate 3); dimers [M(L1)2]2 (M = Zn(II) 1, Hg(II) 4) and a mononuclear [Cd(L2)(phen)], (phen = 1,10-phenanthroline) complex 5. These complexes have been characterised by elemental analysis, IR, UV–Vis., 1H and 13C NMR spectroscopy and their structures have been investigated by X-ray crystallography. In 2 and 3 the metal ions are six-coordinate with two bidentate dithiocarbamate ligands L1 and L2 in an equatorial plane and axially bonded by two Py(N) of the dithiocarbamate ligands on neighbouring molecules thus establishing distorted octahedral geometry (MS4N2) in 2-D polymeric structures. In L1 where the Py(N) is in the 3-position, a centrosymmetric dinuclear complex 1 is formed in which the metal ions adopt square pyramidal geometry. In 1–4, the dithiocarbamate ligands are uniquely bonded to the metal centres in a μ2, κ3-N, S, S bridging-chelating manner. In all the complexes the supramolecular structures are sustained via CH … π (MS2C, chelate) interactions. These unusual interactions have been supported by theoretical calculations. All the complexes show luminescent emissions in the solid phase.

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