New compounds with bridging dicyanamide and bis-chelating 2,2-bipyrimidine ligands: syntheses, structural characterisation and magnetic properties of the two-dimensional materials [Fe2(dca)4(bpym)]H2O and [Fe2(dca)4(bpym)(H2O)2] Academic Article uri icon

abstract

  • The new polymeric, two-dimensional compounds [Fe2(dca)4(bpym)]H2O (1) and [Fe2(dca)4(bpym)(H2O)2] (2) (dca- = dicyanamide anion and bpym = 2,2-bipyrimidine) have been synthesised and characterised by infrared spectroscopy and X-ray crystallography. Both compounds consist of two-dimensional networks of octahedrally co-ordinated iron(II) cations, bridged by bis-bidentate 2,2-bipyrimidine and bridging dicyanamide anions. The metals are in a distorted octahedral environment due to the small bite angle of the bpym ligands [75.3(1) in 1 and 73.7(1) in 2]. The main difference between the two structures is the co-ordination mode of the dca ligands. In compound 1, the iron(II) cation is linked by four dca bridging ligands and by one bis-chelating bpym. In compound 2, each iron cation is linked by two trans-bridging dicyanamide ligands, one bis-chelating bpym and two unidentate ligands in a cis arrangement (one terminal dicyanamide and one water molecule). The main consequence of the different dca co-ordination modes is that each metal cation is connected to four neighbouring metals in 1 but to only three in 2. Magnetic measurements reveal a broad maximum in the m vs. T plots at ca. 11 K for both compounds, which is characteristic of antiferromagnetic exchange interactions between the high-spin iron(II) centres (J = -1.6 cm-1, g = 2.20 for 1 and J = -1.8 cm-1, g = 2.15 for 2).

published proceedings

  • New Journal of Chemistry

author list (cited authors)

  • Triki, S., Thetiot, F., Galn-Mascars, J., Sala Pala, J., & Dunbar, K. R.

citation count

  • 65

complete list of authors

  • Triki, Smaïl||The´tiot, Franck||Galán-Mascarós, Jose-Ramón||Sala Pala, Jean||Dunbar, Kim R

publication date

  • January 2001