Magnetic Multistability in an Anion‐Radical Pimer

Abstract

Radical pimers are the simplest and most important models for studying charge-transfer processes and provide deep insight into p-stacked organic materials. Notably, radical pimer systems with magnetic bi-or multistability may have important applications in switchable materials, thermal sensors, and information-storage media. However, no such systems have been reported. Herein, we describe a new pimer consisting of neutral N-(n-propyl) benzene triimide ([BTI-3C]) and its anionic radical ([BTI-3C] À C) that exhibits rare magnetic multistability. The crystalline pimer was readily synthesized by reduction of BTI-3C with cobaltocene (CoCp 2). The transition occurred with a thermal hysteresis loop that was 27 K wide in the range of 170-220 K, accompanied by a smaller loop with a width of 25 K at 220-242 K. The magnetic multistability was attributed to slippage of the p-stacked BTI structures and entropy-driven conformational isomerization of the side propyl chains in the crystalline state during temperature variation.

Stable Quadruple Helical Tetraradicaloid with Thermally Induced Intramolecular Magnetic Switching

“…50,51 In addition, fine-tuning of the above parameters in a molecular species can lead to a molecule with two or more accessible magnetic states. Thus, the properties exist in two or more interchangeable phases [52][53][54][55] modulated by external stimuli (temperature, pressure, light, etc. ), which are highly desirable for the development of organic magnetic switching materials.…”

Magnetic Transition in Organic Radicals: The Crystal Engineering Aspects

“…72 Similarly, conformational changes in a propyl group exhibit a rare magnetic multistability in the anion-radical pimer consisting of neutral N-(n-propyl) benzene triimide ([BTI-3C]) and its anionic radical ([BTI-3c] − *) (Figure 13, left). 108 At 170 K, one of the three propyl groups adopts a gauche conformation, while the other two adopt an anti conformation. A larger degree of stacking between the pimer has also been observed when the temperature was elevated to 211 K, with all three propyl groups adopting the anti conformation (Figure 13, right).…”

“…Similarly, conformational changes in a propyl group exhibit a rare magnetic multistability in the anion-radical pimer consisting of neutral N -( n -propyl) benzene triimide ([BTI-3C]) and its anionic radical ([BTI-3c] −* ) (Figure , left) . At 170 K, one of the three propyl groups adopts a gauche conformation, while the other two adopt an anti conformation.…”

Magnetic Multistability in an Anion‐Radical Pimer

“…To reveal the phase transitions in crystalline [BTI-3C] 2 À C CoCp 2 + , we further examined the crystal structures at 170, 211, 218, and 250 K. [9] In general, while the crystal space group for all the tested temperatures remained identical (triclinic, P " 1), small differences in cell parameters in terms of axis a, angle g, and cell volume V were observed (see Table S1). The two A molecules in the AA pimer stack in an eclipsed fashion, as do the B molecules in the BB pimer (see Figure S2), whereas the neighboring A and B molecules were slipped relative to each other (Figure 4).…”