A novel two-step Fe–Au type spin-crossover behavior in a Hofmann-type coordination complex {Fe(4-methylpyrimidine)₂[Au(CN)₂]₂}

Abstract

<p>A Hofmann-type two-step spin-crossover (SCO) complex with a pyrimidine derivative ligand was synthesized.</p>

Effects of Both Methyl and Pyrimidine Groups in Fe–Ag Spin-Crossover Hofmann-Type Complex {Fe(4-Methylpyrimidine)2[Ag(CN)2]2}

“…The details of the crystal structure parameters of 1Ag are presented in Table S1. In Table , a comparison between 1Ag and previously synthesized 1Au is shown. As can be seen from the table, the space group of 1Ag is Pccn , whereas that of 1Au is Pbcm , suggesting that the stacking of the Hofmann-type layer in 1Ag is different from that in 1Au .…”

“…Thus, numerous Fe-type, Hofmann-type complexes have been investigated using this spectroscopic technique. − Following the first report on the Mössbauer effect of 191 Ir in 1958 by Mössbauer, Pound described in 1959 that effect in 57 Fe for the first time . Recently, we have investigated a Hofmann-type complex bearing a pyrimidine-type ligand, i.e., {Fe­(4-methylpyrimidine) 2 [Au­(CN) 2 ] 2 } ( 1Au ) . That contains a Au–Au interaction and no Au–N interaction.…”

“…As a result, 1Au is isostructural to pyridine-type complex. Hofmann-type complexes with pyrimidine-type ligands are rarely reported compared with those having pyridine- or pyrazine-type ligands . One reason is that type ligand can act as a bridging ligand between two Fe centers, and a coordination polymer does not show a Hofmann-type structure as result.…”

“…33 Recently, we have investigated a Hofmann-type complex bearing a pyrimidine-type ligand, i.e., {Fe(4methylpyrimidine) 2 [Au(CN) 2 ] 2 } (1Au). 34 That contains a Au−Au interaction and no Au−N interaction. As a result, 1Au is isostructural to pyridine-type complex.…”

“…Hofmann-type complexes with pyrimidine-type ligands are rarely reported compared with those having pyridine-or pyrazine-type ligands. 34 One reason is that type ligand can act as a bridging ligand between two Fe centers, and a coordination polymer does not show a Hofmann-type structure as result. Here, we describe the synthesis of a new Hofmann-type complex, {Fe(4methylpyrimidine) 2 [Ag(CN) 2 ] 2 } (1Ag), and analyze the differences between the structural and magnetic properties of 1Au and 1Ag.…”