Cooperative Magnetism in Crystalline N-Aryl-Substituted Verdazyl Radicals: First-Principles Predictions and Experimental Results.
We report on a series of eight diaryl-6-oxo-verdazyl radicals containing a tert-butyl group at the C(3) position with regard to their crystal structure and magnetic properties by means of magnetic susceptibility measurements in combination with quantum chemical calculations using a first-principles bottom-up approach. The latter method allows for a qualitative prediction and detailed analysis of the correlation between the solid-state architecture and magnetic properties. Although the perturbation in the molecular structure by varying the substituent on the N-aryl ring may appear small, the effects upon the structural parameters controlling intermolecular magnetic coupling interactions are strong, resulting in a wide spectrum of cooperative magnetic behavior. The non-substituted 1,5-diphenyl-tert-butyl-6-oxo-verdazyl radical features a ferromagnetic one-dimensional spin ladder type magnetic network-an extremely rarely observed phenomenon for verdazyl radicals. By varying substituents at the phenyl group, different non-isostructural compounds were obtained with widely different magnetic motifs ranging from linear and zigzag one-dimensional chains to potentially two-dimensional networks, from which we predict magnetic susceptibility data that are in qualitative agreement with experiments and reveal a large sensitivity to packing effects of the molecules. The present study advances the fundamental understanding between solid-state structure and magnetism in organically based radical systems.
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Steffen
S
Eusterwiemann
Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Thomas
T
Dresselhaus
Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149, Münster, Germany.
Carsten
C
Doerenkamp
Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149, Münster, Germany.
Oliver
http://orcid.org/0000-0002-9480-3888
O
Janka
Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149, Münster, Germany.
Oliver
O
Niehaus
Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Anja
A
Massolle
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Constantin G
CG
Daniliuc
Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149, Münster, Germany.|Present address: Instituto de Física em Sao Carlos, Universidade de Sao Paulo, Avenida Trabalhador Saocarlense 400, Sao Carlos, SP, 13566-590, Brazil.
Hellmut
http://orcid.org/0000-0002-6536-0117
H
Eckert
Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149, Münster, Germany.
Rainer
R
Pöttgen
Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Johannes
J
Neugebauer
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Armido
http://orcid.org/0000-0002-1706-513X
A
Studer
cooperative effects; electron spin resonance; ferromagnetic interactions; organic magnetism; structure-property relationships; verdazyl radicals