A Metamagnetic Two-Dimensional Molecular Material with Nickel(II) and Azide

✍ Scribed by Montserrat Monfort; Immaculada Resino; Joan Ribas; Helen Stoeckli-Evans

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 100 KB
• Volume: 39
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/(sici)1521-3773(20000103)39:1<191::aid-anie191>3.0.co;2-f

✦ Synopsis

Until a few years ago, the main aim of magnetochemical research was to show that molecular magnetism could lead to the development of new magnetic materials. One strategy for the design of molecular-based magnets involves assembling transition metal ions in one-, two-, or three-dimensional networks. We are currently studying materials formed from the interaction of transition metal ions with the azido ligand. The azido bridge is a versatile and efficient magnetic coupler; it may transmit either antiferro-or ferromagnetic interactions. Working with Ni II salts and diamines as blocking ligands, for a Ni/diamine ratio of 1/1 four positions in the coordination sphere of the nickel are free. These positions can be occupied by four azido bridges. The most remarkable species obtained to date are the neutral polymeric compounds [Ni(m-N 3 ) 2 -(diamine)] n : three one-dimensional systems showing global ferromagnetic behavior and metamagnetism at low temperature, [2] five one-dimensional complexes with alternating endon (EO) and end-to-end (EE) azido bridges in different sequences showing global anti-ferromagnetic behavior, [3±6] (0.170 g, 52 % yield). Elemental analysis calcd (%) for C 28 H 44 O 14 NKTi: C 47.66, H 6.28, N 1.99; found: C 47.43, H 6.27, N 2.06; m.p. 124 ± 125 8C (decomp); IR (THF): n Ä 1930 (m), 1793 cm À1 (s) (CO); 1 H NMR (300 MHz, [D 8 ]THF, 0 8C, TMS): d 6. 16 (m, 2 H, pyrrolyl), 5.40 (m, 2 H, pyrrolyl), 3.62 (s, 40 H, [15]crown-5); 13 C{ 1 H}(75 MHz, [D 8 ]THF, 0 8C, TMS): d 289 (s, CO), 114 (s, pyrrolyl), 99 (s, pyrrolyl), 69 (s, [15]crown-5).