Spontaneous Magnetization in a Sulfur–Nitrogen Radical at 36 K

Abstract

group P2,,,; a =14.828(2). h = 11.513(1), c =16.637(2)A. 0 =112.735(4). V = 2619.5(5) A', 2 = 4 , pidlid =1.373 gem-,; p = 4.25 m m -' ; max. absorption correction factor l.60:20max =115,24';Cu,,radiation; T = 298K:O-28scan;reflectionscollectedjunique!used, 3767/3579 (R,,, = 0.0219)/3577; parameters refined, 352; Rl!xR2 [2794 reflections with I > 2a/], 0.0576/0.1579; GOF = 1.029; [ A / GI,,, = 0.003; [A&JAp]*," 0.373/ -0.308 eA-3, structure solution and refinement with the programs SHELXS-86 and SHELXL-93: H atoms of 1.10phenanthroline were located by difference maps and refined isotropically, the rest were introduced at calculated positions as riding on bonded atoms; all non-H atoms refined anisotropically (except atoms of the solvent methanol which refined isotropically with occupancy fixed at 10.5. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-179-98. Copies of the data can be obtained free of charge on application to The Director, CCDC, 12 Union Road.

High-Temperature Magnetic Ordering in a New Organic Magnet

“…Above 36 K, the magnetic susceptibility is consistent with a paramagnetic compound which exhibits strong antiferromagnetic exchange interactions [10]. Below 36 K an out-of-phase component is observed in the ac susceptibility at 1 Hz, indicative of the presence of net magnetic moments in the sample (Fig.…”

“…This is precisely a characteristic of the b-phase of 1 which crystallizes in the noncentrosymmetric polar space group Fdd2 [10]. The magnitude of the spontaneous magnetic moment is dependent on the canting angle.…”

“…, 1, which is polymorphic [9,10]. The a-phase orders antiferromagnetically at 8 K [9], whereas preliminary magnetic measurements of the b-phase, 1b, indicate the onset of a spontaneous magnetic moment below 36 K [10], an exceptionally high temperature for a purely organic free radical.…”

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

“…The compounds 1 and 2 seem to have negligible intermolecular transfer interactions according to their insulating features and Curie-like magnetic behaviors. The radicals 4, 15, 84 and 16 [85][86][87] (Chart 4) have been developed based on the concept of the push-pull effect. Furthermore, the addition of the dithiadiazolyl ring is very efficient to stabilize radicals.…”

“…88 They have a small t since there are no special intermolecular interactions between the radical moieties for appropriate packing. Hence, 16 is a typical Mott insulator and exhibits a weak ferromagnetism with canted antiferromagnetic interactions with T c ¼ 35:5 K. 85,86 The transition temperature is enhanced to 64.5 K by an application of pressure of 1.6 GPa. 87 Some selected organic conductors of neutral radicals and biradicals are presented in Table 5.…”