Alkyl side chain on the 1-methylimidazolium ring of countercation modulating thermal and magnetic properties of metal-dithiolene complexes

• Multi-step solid to solid state phase transition was observed for 1.
• 1 exhibits weak paramagnetism and 2 shows spin gap in the low-temperature phase.
• The cations and anions formed mixed column along the crystallographic a-axis direction in the crystal of 1.

Two low-dimensional ion-pair compounds [1,5-bis(1-methylimidazolium)pentane][Ni(mnt)2]2 (1) and [1,9-bis(1-methylimidazolium)nonane][Ni(mnt)2]2 (2) (mnt2− = maleonitriledithiolate) were designed and synthesized. The cations and anions formed mixed column along the crystallographic a-axis direction in the crystal of 1·0.5DMF. Two compounds display different thermal and magnetic behaviors. Multi-step solid to solid state phase transition was observed for 1 by DSC. 1 exhibits weak paramagnetism over the temperature range of 2–400 K and 2 shows spin gap in the low-temperature phase. Thus by changing of the alky chain length of the counter-cation allows the modulation thermal and magnetic behaviors for such system.

Multi-step solid to solid state phase transition was observed for 1 by DSC. 1 exhibits weak paramagnetism over the temperature range of 2–400 K and 2 shows spin gap in the low-temperature phase.Figure optionsDownload as PowerPoint slide