Thermally induced dimensionality changes in derivatives of a "super stable" Blatter radical

• Published in: Physical chemistry chemical physics : PCCP Vol. 25; no. 34; pp. 22813 - 22818
• Main Authors: Camargo, Bruno, Zajcewa, Irina, Pietrzak, Anna, Obijalska, Emilia, Szczytko, Jacek, Kaszy ski, Piotr
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 30.08.2023
• Subjects: Antiferromagnetism; Magnetic measurement; Structural analysis; Superconducting quantum interference devices
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp01298k

Two derivatives of a "super stable" Blatter radical (1,3-diphenyl-7-trifluoromethyl-1,4-dihydrobenzo[ e ][1,2,4]triazin-4-yl) with N(1)-Ar = 2-CF 3 C 6 H 4 and 2-MeOC 6 H 4 were obtained and investigated using XRD and SQUID magnetometry methods. The investigation revealed strong antiferromagnetic interactions in both radicals, which are described using the Hatfield model. For the latter radical, an abrupt and reversible change in the χ ( T ) plot was observed at 29 K. It was ascribed to a structural transition, consistent with a two-dimensional to one-dimensional thermally activated crossover, as supported by specific heat measurements ( C vH vs. T ). It is suggested that the transition is related to an order-disorder transition of the CF 3 group, which is corroborated using XRD structural analysis. A discontinuity in the χ ( T ) plot at 29 K is linked to the rotational order-disorder transition of the CF 3 group in the solid-state of a radical.