Crystallographic evidence for reversible symmetry breaking in a spin-crossover d7 cobalt(II) coordination polymer

All in a spin: A cobalt(II) coordination polymer has a highly cooperative spin-crossover (SCO) behavior with a small hysteresis loop (see picture; HS=high spin, LS=low spin). The correlation of the magnetic properties with the crystal structures was determined at different temperatures. This study reveals an unprecedented reversible symmetry breaking in a d7 SCO coordination polymer.This work was supported by the DST and CSIR, India. J.S.C. thanks the Spanish MICINN through CTQ2009-06959 for the research fellowship “Juan de la Cierva” (18-08-463B-750). J.R. also thanks the Spanish MICINN through CTQ2009-07264.Peer Reviewe