A new spin crossover heterometallic FeIIAgI coordination polymer with the [Ag2(CN)3]− unit: crystallographic and magnetic study

Abstract

The novel bimetallic Fe^IIAg^I thermal-induced spin crossover coordination polymer {Fe^II(3,5-dimethylpyridine)₂[Ag^I₂(CN)₃][Ag^I(CN)₂]}_n was synthesized by one-pot reactions between 3,5-dimethylpyridine and K[Ag^I(CN)₂] in the presence of Fe^II salt (FeSO₄·(NH₄)₂SO₄·6H₂O). Magnetic studies demonstrate the occurrence of a spin transition. The crystal structure has been studied at 293 K and 80 K. The compound is made up of unprecedented three-dimensional networks topology of Fe^II ions bridged by binuclear [Ag^I₂(CN)₃]⁻ and mononuclear [Ag^I(CN)₂]⁻ units; [Ag^I₂(CN)₃]⁻ anion is very rare. In this complex, the presence of the Ag^I ions plays a significant role in increasing the dimensionality and cooperatively due to the triangular argentophilic interactions.