A magnetostructural investigation of an abrupt spin transition for 1-phenyl-3-trifluoromethyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl

Christos P Constantinides; Andrey A Berezin; Georgia A Zissimou; Maria Manoli; Gregory M Leitus; Michael Bendikov; Michael R Probert; Jeremy M Rawson; Panayiotis A Koutentis

doi:10.1021/ja5063746

A magnetostructural investigation of an abrupt spin transition for 1-phenyl-3-trifluoromethyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl

J Am Chem Soc. 2014 Aug 27;136(34):11906-9. doi: 10.1021/ja5063746. Epub 2014 Aug 15.

Authors

Christos P Constantinides¹, Andrey A Berezin, Georgia A Zissimou, Maria Manoli, Gregory M Leitus, Michael Bendikov, Michael R Probert, Jeremy M Rawson, Panayiotis A Koutentis

Affiliation

¹ Department of Chemistry, University of Cyprus , P.O. Box 20537, 1678 Nicosia, Cyprus.

PMID: 25093450
DOI: 10.1021/ja5063746

Abstract

1-Phenyl-3-trifluoromethyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl is the first example of a hydrazyl radical that shows a reversible sharp spin transition fully completed within 5(1) K. The nominally first-order transition takes place at ca. 58(2) K and proceeds via subtle changes of intra- and interstack interactions between two similar structural phases. The low-temperature phase (5-60 K) is diamagnetic and has a singlet ground state (2Jexp = -166.8 cm(-1), gsolid = 2.0042, ρ = 0.2%) stemming from a multicenter two-electron interaction. The high-temperature phase (60-300 K) is paramagnetic as a result of noninteracting S = 1/2 spins arising from weakly bound dimers.