Synthesis, structure and spectroscopy of trinuclear [Cu(mbpzbpy)NO3]2[Cu(NO3)4](CH3CN)2 without magnetic exchange coupling (mbpzbpy=6,6′-bis(3,5-dimethyl-N-pyrazolmethyl)-2,2′-bipyridine)
作者:Palanisamy Uma Maheswari、Ilpo Mutikainen、Urho Turpeinen、Manuel Quesada、Jan Reedijk
DOI:10.1016/j.poly.2011.12.025
日期:2012.2
A new copper(II) compound with an unusual composition containing the tetranitratocuprate(II) is reported. [Cu(mbpzbpy)NO3](2)[Cu(NO3)(4)]center dot 2(CH3CN) in which mbpzbpy = 6,6'-bis(3,5-dimethyl-N-pyrazolmethyl)-2,2'-bipyridine, has been synthesized and fully characterized, including the X-ray and the magnetic susceptibility. The X-ray structure of the complex depicts Cu(II) centers with entirely different coordination environments. The Cu1 ion is coordinated to an embracing N-4 ligand mbpzbpy and one oxygen atom of an axial nitrate anion, giving rise to a square-pyramidal geometry. The Cu2 ion exhibits a highly distorted coordination environment formed by four bidentate nitrate ions. Also, in the asymmetric unit of the complex, two optically related, right and left-handed enantiomers of Cu1 units are connected to one Cu2 center, through a weak Cu-O bond. Magnetic susceptibility studies down to 5 K and low temperature and room temperature EPR indicate that only a very weak magnetic exchange is present, despite the short Cu center dot center dot center dot Cu contact distances of 4.88 angstrom. (C) 2011 Elsevier Ltd. All rights reserved.