Ferro- or antiferromagnetism? Heisenberg chains in the crystal structures of verdazyl radicals

Author(s)

Eusterwiemann, Steffen ^[1] ; Doerenkamp, Carsten ^{[2, 3]} ; Dresselhaus, Thomas ^{[1, 4]} ; Janka, Oliver ^[5] ; Daniliuc, Constantin G. ^[1] ; Poettgen, Rainer ^[5] ; Studer, Armido ^[1] ; Eckert, Hellmut ^{[2, 3]} ; Neugebauer, Johannes ^{[1, 4]}

Affiliation

^[1] Westfalische Wilhelms Univ Munster, Organ Chem Inst, Corrensstr 40, D-48149 Munster - Germany

^[2] Westfalische Wilhelms Univ Munster, Inst Phys Chem, Corrensstr 28-30, D-48149 Munster - Germany

^[3] Univ Sao Paulo, Inst Fis Sao Carlos, Ave Trabalhador Saocarlense 400, BR-13566590 Sao Carlos, SP - Brazil

^[4] Westfalische Wilhelms Univ Munster, Ctr Multiscale Theory & Computat, Corrensstr 40, D-48149 Munster - Germany

^[5] Westfalische Wilhelms Univ Munster, Inst Anorgan & Analyt Chem, Corrensstr 28-30, D-48149 Munster - Germany

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 20, n. 35, p. 22902-22908, SEP 21 2018.
• Web of Science Citations: 0

Abstract

In this study, we address the question of the origin of ferromagnetic or antiferromagnetic interactions in alkynyl-substituted 1,5-diphenyl-6-oxo verdazyl radicals. While a TMS-alkynyl derivative (3) shows antiferromagnetic ordering at low temperatures, the corresponding deprotected alkynyl verdazyl (4) shows ferromagnetic interactions. For both compounds, magnetic Heisenberg chains are characteristic, which were studied systematically by means of X-ray crystallography and quantum chemical calculations. Ferromagnetic interactions are rarely found in such radicals. Therefore, uncovering such structure-property relationships is of crucial importance in order to understand and design promising ferromagnetic networks. Using this knowledge, we were able to design and crystallize diyne derivatives showing comparable solid state characteristics and therefore antiferro- and ferromagnetic Heisenberg chain structures. We show that the understanding of such property-structure relationships is adequate for the design of organic-magnetic materials with defined cooperative effects within the class of verdazyl radicals. (AU)

• FAPESP's process: 17/06649-0 - New Optical Materials based on Rare-Earth Doped Oxyfluoride Glasses and Ceramics: Structural Studies by Electron Paramagnetic Resonance Methods
• Grantee: Carsten Doerenkamp
• Support type: Scholarships in Brazil - Post-Doctorate