Crystal Engineering of FeII Spin Crossover Coordination Polymers Derived from Triazole or Tetrazole Ligands

Abstract

The past decade has witnessed intense research activity in the area of Fe(II) spin crossover coordination polymers, which are structurally diverse and functionally intriguing materials. In this endeavor, a less exploited series of ligands have been selected among various N-donor triazole and tetrazole molecules. Developing conventions that allow the tailoring of such functional materials with predictable architecture and properties is an important objective and current interest in crystal engineering. However, detailed knowledge on the structure-property correlation is still scanty due to the small number of crystal structures of such compounds. The principal focus is to decipher the effect of various supramolecular factors such as intermolecular interactions, hydrogen bonding etc., on the resultant Fe(II) coordination polymers. This tutorial review aims at highlighting some of the developments of such structurally diverse and functionally intriguing 1D polymeric chains, 2D and 3D networks built from triazole or tetrazole ligands exhibiting fascinating spin crossover phenomena.

Pressure Sensor via Optical Detection Based on a 1D Spin Transition Coordination Polymer

“…Thus, SCO materials are considered as pressure sensors [ 7 , 10 ]. A remarkable family is represented by 1D Fe(II) coordination polymers with 1,2,4-triazole ligands [ 11 , 12 ], which show marked colour changes making this family of materials suitable to be used as temperature and pressure sensors with optical detection [ 7 ]. In Figure 1a , the pressure applied to the Fe(II) material is lower than the critical pressure, P c , and the SCO compound appears white (HS state).…”

Design and Control of Cooperativity in Spin-Crossover in Metal–Organic Complexes: A Theoretical Overview

“…[Fe(btr) 3 ][(ClO 4 ) 2 ] [11] represents the first 3-d SCO coordination polymer. For a concise review on 1-d, 2-d and 3-d Fe(II) polymers, please see Reference[11].…”

One‐Dimensional Looped Chain and Two‐Dimensional Square Grid Coordination Polymers: Encapsulation of Bis(1,2,4‐Triazole)‐trans‐cyclohexane into the Voids

“…In fact these 2D materials are not much explored, despite of some examples where it showed remarkable applications in biomimetic enzymes, molecular sieves membranes, gas separation catalysis and photoluminescence . Recently we reported a 2D corrugated sheet coordination polymer derived from Fe II and a tris‐tetrazole ligand, which showed remarkable spin crossover phenomena in both bulk single crystals and in exfoliated nanosheets …”