Back to back 2,6-bis(pyrazol-1-yl)pyridine and 2,2′:6′,2"-terpyridine ligands: Untapped potential for spin crossover research and beyond

2,6-Bis(pyrazol-1-yl)pyridine (L1) and 2,2:6',2 ''-terpyridine (L2) are popular ligands for use in a wide range of applications in coordination chemistry. Both ligands are capable of forming metal complexes with highly interesting and potentially exploitable properties: luminescence, catalytic redox activity and magnetic spin crossover (SCO). SCO materials have received attention because of the potential for incorporation into commercially relevant technologies such as sensors and information storage media. This review explores the potential of 'back to back' L1 SCO polymers using reported examples, and looks towards the larger L2 chemical library, covering the coordination chemistry with a focus on magnetic properties. In principle, polymeric coordination materials are easier to process and may offer an easier route to tuning properties that are dependent on the electronic environment. It is the intention of this review to highlight the potential of these materials, with the goal of promoting the development of multifunctional SCO hybrids. (C) 2017 Elsevier B.V. All rights reserved.