ISSN:
1572-901X
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Summary New coligand isomers of composition Cu{N(CN)2}2(pz)2 and Cu{pz · N(CN)2}2 (pz = pyrazole) were prepared and studied by measuring their magnetic susceptibilities up to 4.2K and by aid of their e.s.r., ligand field and i.r. spectra. The susceptibility data have been analysed with various models for the exchange-coupled copper(II) polymers. It is shown that the resultant exchange coupling is ferromagnetic for Cu{N(CN)2}2(pz)2 (J ∼ 1.1 - 1.4 cm−1) but antiferromagnetic for Cu{pz · N(CN)2}2 (J ≈ −0.4 cm−1). A polymeric chain structure is proposed for Cu{N(CN)2}2(pz)2 havingpseudo-octahedrally coordinated copper(II) and CN-bridging dicyanamide ligands. Its coligand isomer contains anionic chelate ligands, formed by nucleophilic addition between N(CN)2 and pz in the copper(II) coordination sphere, and giving with this central atom a square-planar system. Definite, but slight axial interaction takes place between these structure units.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01386883
