Spin transitions in a dithiazolyl radical: preparation, crystal structures, and magnetic properties of 3-cyanobenzo-1,3,2-dithiazolyl, C7H3S2N2.
The incorporation of the electronegative cyano group into the structure of the title dithiazolyl radical 1 induces a lamellar packing motif that favors spin-transition behavior. Variable-temperature magnetic studies on 1 reveal a reversible phase transition at 250 K between a diamagnetic low-temperature phase and a paramagnetic high-temperature phase. X-ray crystal structures at 180(2) and 300(2) K reveal that both phases crystallize in the space group P2(1)/c, with the phase transition associated with a doubling of the crystallographic a axis. The concomitant change in magnetic properties is associated with a change from a paramagnetic regular pi stack of radicals and a diamagnetic distorted pi stack in which an energy gap opens up at the Fermi level corresponding to a Peierls-like transition.
Alberola
Antonio
A
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Collis
Rebecca J
RJ
Humphrey
Simon M
SM
Less
Robert J
RJ
Rawson
Jeremy M
JM