Novel self-assembled supramolecular architectures of Mn(II) ions with a hybrid pyrazine-bipyridine ligand

Dalton Trans. 2013 Jul 14;42(26):9746-54. doi: 10.1039/c3dt50352f. Epub 2013 May 20.

Abstract

A new hybrid pyrazine-bipyridine ligand L (C26H20N6) and its complexes with Mn(NO3)2, Mn(ClO4)2, MnCl2 and MnBr2 have been synthesised. By the self-assembly of L and Mn(II) ions three different kinds of supramolecular complexes have been obtained: binuclear baguette complex [Mn2L(H2O)6](NO3)4·2.5H2O 1 and tetranuclear [2 × 2] grid-type complex [Mn4L4](ClO4)8·2.5(CH3CN)·2CH3OH 2 and mononuclear complexes [MnL2]X2 (where X = Cl(-)3 and X = Br(-)4). Crystal structures and magnetic properties of Mn(II) complexes 1 and 2 have been also investigated. The crystal structures reveal that in both 1 and 2 complexes the Mn(II) ions have coordination number 6 and distorted octahedral coordination geometry. In 2 four metal cations and four ligands have assembled into a grid-type [2 × 2] array, with a perchlorate anion occupying the central cavity, with clearly a good fit for the center of the cavity. The perchlorate anion, in contrast to the nitrate anion, probably acts as a template in the formation of tetranuclear grid-type complexes. Magnetic susceptibility measurements indicate that the Mn(II) ions are all high spin, and in both 1 and 2 complexes there are weak antiferromagnetic interactions between Mn(II) ions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Ions / chemistry
  • Ligands
  • Macromolecular Substances / chemical synthesis
  • Macromolecular Substances / chemistry
  • Manganese / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis*
  • Organometallic Compounds / chemistry
  • Pyrazines / chemistry*
  • Pyridines / chemistry*

Substances

  • Ions
  • Ligands
  • Macromolecular Substances
  • Organometallic Compounds
  • Pyrazines
  • Pyridines
  • Manganese