Interplay between spin crossover and proton migration along short strong hydrogen bonds.

ABSTRACT: The iron(ii) salt [Fe(bpp)₂](isonicNO)₂·HisonicNO·5H₂O (1) (bpp = 2,6-bis(pyrazol-3-yl)pyridine; isonicNO = isonicotinate N-oxide anion) undergoes a partial spin crossover (SCO) with symmetry breaking at T ₁ = 167 K to a mixed-spin phase (50% high-spin (HS), 50% low-spin (LS)) that is metastable below T ₂ = 116 K. Annealing the compound at lower temperatures results in a 100% LS phase that differs from the initial HS phase in the formation of a hydrogen bond (HB) between two water molecules (O4W and O5W) of crystallisation. Neutron crystallography experiments have also evidenced a proton displacement inside a short strong hydrogen bond (SSHB) between two isonicNO anions. Both phenomena can also be detected in the m

SUBMITTER: Jornet-Molla V 

PROVIDER: S-EPMC8179063 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature