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Towards the Design of Linear Homo‐Trinuclear Metal Complexes Based on a New Phenol‐Functionalised Diazamesocyclic Ligand: Structural Analysis and Magnetism
Author(s) -
Du Miao,
Zhao XiaoJun,
Guo JianHua,
Bu XianHe,
Ribas Joan
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400618
Subject(s) - chemistry , intramolecular force , crystallography , ligand (biochemistry) , octahedron , antiferromagnetism , magnetic susceptibility , square pyramidal molecular geometry , metal , magnetochemistry , metal ions in aqueous solution , diamagnetism , magnetism , ion , crystal structure , stereochemistry , biochemistry , receptor , physics , organic chemistry , quantum mechanics , magnetic field , condensed matter physics
The formation of two novel phenoxo‐bridged linear trimetallic Cu II and Ni II complexes, [Cu 3 (μ‐ L ) 2 ](CH 3 OH) 2 (ClO 4 ) 2 ( 1 ) and [Ni 3 (μ‐ L ) 2 (CH 3 OH) 2 ](ClO 4 ) 2 ( 2 ), with a new diazamesocyclic ligand functionalised by additional phenol donor pendants (H 2 L = N , N′ ‐ bis(2‐hydroxybenzyl)‐1,4‐diazacycloheptane), has been achieved and both complexes have been characterised by IR spectroscopy, elemental analyses, conductivity measurements, thermal analyses and UV/Vis techniques. Single‐crystal X‐ray diffraction analyses revealed that both 1 and 2 have the similar phenoxo‐bridged linear trinuclear cores. For 1 , two terminal and the central Cu II ion are in square‐planar environments with the adjacent intramolecular Cu ··· Cu separation of 2.9376(9) Å. For 2 , however, two terminal Ni II ions are in square‐planar environments and the central Ni II ion assumes an octahedral geometry by axial coordination of two methanol ligands, the adjacent intramolecular Ni ··· Ni distance being 3.007(3) Å. In both cases, the 1,4‐diazacycloheptane (DACH) ring adopts the normal boat configuration. The magnetic properties of complexes 1 and 2 have been investigated by variable‐temperature magnetic susceptibility measurements in the solid state. Complex 1 displays a very strong antiferromagnetic coupling interaction between the neighbouring μ‐phenoxo Cu II centres with a J parameter of −314 cm −1 and the magneto‐structural correlation for such complexes is discussed in detail. For complex 2 , the result indicates that both terminal Ni II ions are diamagnetic and the central Ni II shows typical paramagnetic behaviour. The presence of zero‐field splitting for Ni II with a D parameter of 11 cm −1 , being active at low temperature, is further corroborated by the magnetisation measurement at 2 K. Additionally, the interesting ESR spectra of 1 at different temperatures (from 298 K to 8 K) were investigated and interpreted. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)