Title

Bis[nitrato(N-ethyl-2-hydroxybenzylideniminato-μ-O)copper(II)]

Alternative Title

A novel copper dimer structure

Abstract

The reaction of bis(N-ethyl-2-hydroxybenzylideniminato)nickel(II), Ni(etsal)2, with copper(II) nitrate produced the title complex [Cu(etsal)NO3]2, in the form of crystals large enough for structure determination by x-ray diffraction. Crystal data: P21/c, Z = 2, a = 9.678 (6) Å, b = 9.82 (1) Å, c = 16.267 (7) Å, β = 134.69(4)°, V= 1100 Å3;, R = 3.8%, 1425 reflections. [Cu(etsal)NO3]2 is dimeric with adjacent metal atoms bridged by pairs of phenolic oxygens from the Schiff base ligands. The coppers are five-coordinated with four strong bonds (ranging from 1.93 to 1.99 Å) and a very weak fifth bond with a nitrato oxygen (Cu-O = 2.4 Å) to complete a rough square pyramid. Thus, an approximate comparison can be made with the analogous dimers with halide and alkoxy ligands. Within this approximation, the strength of antiferromagnetic interactions between the neighboring copper atoms (singlet-triplet separation, -2J ≈ 166 cm-1) fits into a series of four-coordinated copper dimers for which -2J decreases with increasing distortion toward tetrahedral geometry, if allowance is made for the perturbing effect of the weak fifth bond, which also weakens the superexchange.

Department(s)

Chemistry

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1976 American Chemical Society (ACS), All rights reserved.


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