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Self‐Penetration—A Structural Compromise between Single Networks and Interpenetration: Magnetic Properties and Crystal Structures of [Mn(dca) 2 (H 2 O)] and [M(dca)(tcm)], M=Co, Ni, Cu, dca=Dicyanamide, N(CN) 2 − , tcm=Tricyanomethanide, C(CN) 3 −
Author(s) -
Jensen Paul,
Price David J.,
Batten Stuart R.,
Moubaraki Boujemaa,
Murray Keith S.
Publication year - 2000
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(20000901)6:17<3186::aid-chem3186>3.0.co;2-v
Subject(s) - dicyanamide , crystallography , rutile , paramagnetism , chemistry , magnetization , antiferromagnetism , materials science , condensed matter physics , magnetic field , ionic liquid , physics , biochemistry , organic chemistry , quantum mechanics , catalysis
The three‐dimensional coordination polymers [Mn(dca) 2 (H 2 O)] ( 1 ) and [M(dca)(tcm)], M=Co ( 2 ), Ni ( 3 ), Cu ( 4 ), dca=dicyanamide, N(CN) 2 − , tcm=tricyanomethanide, C(CN) 3 − , have isomorphous structures. In 1 half the dca ligands coordinate directly (through all three nitrogen atoms) to three Mn atoms (all metal atoms are six‐coordinate), while the other half coordinate to two Mn atoms (through the nitrile nitrogens) and hydrogen bond to water molecules coordinated to a third Mn atom (through the amide nitrogen). This dca⋅H 2 O structural moiety is disordered over a mirror plane, and is replaced by the structurally equivalent tcm ligand in compounds 2 – 4 . The resulting structures display a new self‐penetrating 3,6‐connected (2:1) network topology that can be related to, but is different from, the rutile net. The self‐penetrating [M(dca)(tcm)] network can be viewed as a structural compromise between the two interpenetrating rutile‐like networks of [M(tcm) 2 ] and the single rutile‐like network of α‐[M(dca) 2 ]. The temperature and field dependence of the DC and AC magnetic susceptibilities and magnetisations has been measured for complexes 1 – 4 . Compounds 1 – 3 exhibit long‐range magnetic order with critical temperatures of 6.3 K for 1 , 3.5 K for 2 and 8.0 K for 3 . The Cu II compound 4 does not order and is essentially a paramagnet. Hysteresis measurements of coercive field and remnant magnetisation show that 1, 2 and 3 are soft magnets, 1 being a canted‐spin antiferromagnet (weak ferromagnet), while 2 and 3 are ferromagnets that display some unusual features in their high‐field magnetisation isotherms in comparison to their related α‐[M(dca) 2 ] phases.