Pressure-induced enhancement of magnetic-ordering temperature in an organic radical to 70 K: a magnetostructural correlation.
The structure of the canted antiferromagnet β-p-NCC(6)F(4)CNSSN (1) was determined from synchrotron powder-diffraction studies in the pressure range 0-21.6 kbar. Radical 1 crystallizes in the orthorhombic space group Fdd2, but undergoes an asymmetric contraction of the unit-cell size with increasing pressure. At the molecular level, this contraction of the unit cell is simultaneously accommodated by: 1) an increase in twist angle between aryl and heterocyclic rings; and 2) a shortening of the intermolecular S···N contacts, which propagate the magnetic-exchange pathway. DFT calculations based on the structures in this pressure range revealed an increase in the magnetic-exchange interaction (J) with increasing pressure, and an excellent correlation was observed between J and the magnetic-ordering temperature, which increased from 36 K at ambient pressure up to 70 K at 16 kbar.
Department of Chemistry, The University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Richard I
RI
Thomson
Christopher M
CM
Pask
Gareth O
GO
Lloyd
Masaki
M
Mito
Jeremy M
JM
Rawson