Four‐Step Spin Crossover in a New Cyano‐Bridged Iron‐Silver Coordination Polymer

Abstract

Spin‐crossover complexes with multistep transitions attract much attention due to their potential applications as multi‐switches and for data storage. A four‐step spin crossover is observed in the new iron(II)‐based cyanometallic guest‐free framework compound Fe(2‐ethoxypyrazine)2{Ag(CN)2}2 during the transition from the low‐spin to the high‐spin state. A reverse process occurs in three steps. Crystallographic studies reveal an associated stepwise evolution of the crystal structures. Multiple transitions in the reported complex originate from distinct FeII sites which exist due to the packing of the ligand with a bulky substituent.

Regulating Spin-State Switching by Integrating Polyoxometalate Anion into Spin Crossover System

“…During the SCO process of 1•Mo 8 , the synchronized variation between lattice parameters and magnetic susceptibilities was also detected (Figure S11). 33 The very abrupt changes in the crystallographic parameters around 320 K indicated the loss of solvent molecules. S4).…”

“…During the SCO process of 1·Mo 8 , the synchronized variation between lattice parameters and magnetic susceptibilities was also detected (Figure S11). The very abrupt changes in the crystallographic parameters around 320 K indicated the loss of solvent molecules. For 1·Mo 8 –Na , each 1D cation chain was surrounded by four closest anion chains of [Na­(Mo 8 O 26 )] 3– in four perpendicular directions (Figure S12), in which the cation chains were completely separated with the largest interchain Fe···Fe distance (12.232–14.029 Å).…”