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Two Diammonium Copper Azides with Similar Layerlike Magnetic Substructures Made of Chains of Serially Connected Cu 6 Rings Show Cation‐Modulated Magnetism
Author(s) -
Liu Tao,
Yang YanFei,
Wang ZheMing,
Gao Song
Publication year - 2008
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200800012
Subject(s) - azide , antiferromagnetism , crystallography , ferromagnetism , copper , cationic polymerization , magnetism , protonation , chemistry , ring (chemistry) , ion , stereochemistry , condensed matter physics , polymer chemistry , physics , organic chemistry
Abstract We present here the first examples of Cu–azide compounds synthesized by using protonated diamine ions as cationic templates: (dmenH 2 )[Cu 6 (N 3 ) 14 ] and (trimenH 2 )[Cu 6 (N 3 ) 14 ] (dmenH 2 2+ : N , N ′‐dimethylethylenediammonium; trimenH 2 2+ : N , N , N ′‐trimethylethylenediammonium). Both compounds possess a similar, rarely observed anionic Cu–azide layer, which consists of [Cu 6 (N 3 ) 14 2− ] n anionic chains linked by asymmetric end‐to‐end azido bridges. The chain, in turn, is made up of elongated Cu 6 rings, with double and single end‐on azido linkages between the square‐planar Cu 2+ sites within the ring and double end‐on azido bridges serially connecting the rings. The molecular geometry results in ferromagnetic interactions within the Cu–azide layer in both compounds. The interlayer separations are determined by the cations, with the shortest interlayer Cu⋅⋅⋅Cu separations being 8.016 Å for the dmenH 2 2+ compound and 9.106 Å for the trimenH 2 2+ compound. These different interlayer separations tune the magnetic properties of the two materials. The dmenH 2 2+ compound displays long‐range antiferromagnetic ordering at lowtemperature and short‐range ferromagnetic interaction at high temperature, while only short‐range ferromagnetism was observed in the trimenH 2 2+ compound at 2–300 K.