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

Iron(II) Complexes of 4-(Alkyldisulfanyl)-2,6-di(pyrazolyl)pyridine Derivatives. Correlation of Spin-Crossover Cooperativity with Molecular Structure Following Single-Crystal-to-Single-Crystal Desolvation

“…Derivatives of [Fe(bpp) 2 ] 2+ (bpp = 2,6-bis(pyrazol-1-yl)pyridine; Chart 1 ) can be prepared with a variety of pyridyl and/or pyrazolyl substituents, which often exhibit SCO at accessible temperatures. 27 , 28 , 30 , 31 The library of [Fe(bpp R ) 2 ]X 2 (X – = a monovalent anion) compounds is now large enough to allow structure–function correlations to be derived. 32 , 33 Iron complexes of 4-alkylsulfanyl-2,6-bis(pyrazol-1-yl)pyridine ligands (bpp R ; R = SMe, S i Pr, S t Bu) have been particularly useful.…”

Structural Transformations and Spin‐Crossover in [FeL2]2+ Salts (L=4‐{tert‐Butylsulfanyl}‐2,6‐di{pyrazol‐1‐yl}pyridine): The Influence of Bulky Ligand Substituents

“…[7] Iron(II)c omplexes of 2,6-di-(pyrazol-1-yl)pyridine (bpp) derivatives are widely used in SCO research, since aw ide range of substituents can be appended to the bpp framework. [8][9][10] Thus bpp derivatives bearing fluorescent, [11][12][13] photoactive, [14,15] redox-active, [16] conducting, [17] magnetic, [18,19] amphiphilic [20,21] and tether group substituents [13,22,23] have all been prepared, as have ditopic bpp ligands. [10,12,15,19,21,24,25] Iron complexes of these novel ligands often exhibit useful and/or multifunctional SCO switching properties.…”

An iron(ii) coordination polymer of a triazolyl tris-heterocycle showing a spin state conversion triggered by loss of lattice solvent

“…9 That flexibility has been exploited in ditopic "backto-back" bpp ligands, to prepare coordination polymers or other assembly structures of [Fe(bpp) 2] 2+ centres. 10 However the resultant materials are often poorly crystalline, with ill-defined SCO switching properties. 11 We therefore sought other ways to link [Fe(bpp)2] 2+ -type centres into larger assemblies.…”