The variable temperature magnetic susceptibility, X-ray crystallography, and Mössbauer and Raman spectra of a new dinuclear complex-based one-dimensional coordination polymer [{FeII2(NCS)2(μ-bpypz)2}(μ-4,4′-bpy)]·MeOH demonstrated a steep one-step [HS–HS] to [LS–LS] spin transition.
![Graphical abstract: A steep one-step [HS–HS] to [LS–LS] spin transition in a 4,4′-bipyridine linked one-dimensional coordination polymer constructed from a pyrazolato bridged Fe(ii) dimer](http://hg.y866.cn/compound/lib/scimg/usr/1/B512266J.jpg)
