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Controlled Synthesis and Magnetic Properties of 2D and 3D Iron Azide Networks $\rm{^{2}_{\infty }}$ [Fe(N 3 ) 2 (4,4′‐bpy)] and $\rm{^{3}_{\infty }}$ [Fe(N 3 ) 2 (4,4′‐bpy)]
Author(s) -
Fu Aihua,
Huang Xiaoying,
Li Jing,
Yuen Tan,
Lin Chyan Long
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020517)8:10<2239::aid-chem2239>3.0.co;2-7
Subject(s) - azide , crystallography , combinatorics , condensed matter physics , physics , materials science , chemistry , mathematical physics , mathematics , discrete mathematics , organic chemistry
Controlled synthesis of transition metal complexes with mixed ligands has led to two new compounds with the same empirical formula [Fe(N 3 ) 2 (4,4′‐bpy)] (4,4′‐bpy=4,4′‐ bipyridine). The compound 2D‐[Fe(N 3 ) 2 (4,4′‐bpy)] ( I ) contains end‐on (EO) bridging azido ligands. It crystallizes in the orthorhombic crystal system, space group Cmmm (No. 65): a =11.444(2) Å, b =15.181(3) Å, c =3.458(1) Å, V =600.8(2) Å 3 , and Z =2. The compound 3D‐[Fe(N 3 ) 2 (4,4′‐bpy)] ( II ) contains end‐to‐end (EE) azido bridges. It belongs to the tetragonal crystal system, space group P 4 1 2 1 2 (No. 92): a =8.132(1) Å, b =8.132(1) Å, c =16.708(3) Å, V =1104.9(5) Å 3 , and Z =4. Crystals of I and II have been grown by the diffusion method. Phase‐pure samples of both compounds have been obtained by means of an optimal solution synthesis. Spontaneous long‐range magnetic ordering was found in both I and II , with I being a metamagnet, and II being a ferromagnet. For I , in the low‐field region, multiple transitions at T N1 =20 K and T N2 =5 K were observed, and these indicated the existence of Fe moment reorientation. Heat capacity measurements on II confirmed ferromagnetic transition at T C =20 K.