In:
Bulletin of the Chemical Society of Japan, Oxford University Press (OUP), Vol. 57, No. 11 ( 1984-11-01), p. 3307-3311
Abstract:
Several iron(III) complexes with planar unsymmetrical quadridentate Schiff bases composed of 1:1:1 condensation products of acetylacetone, ethylenediamine, and each of salicylaldehyde and o-hydroxyacetophenone have been prepared and characterized, where the Schiff bases are abbreviated as [H2salacen] and [H2hapacen], respectively. The effective magnetic moment of [FeCl(hapacen)] increases gradually from 3.46 BM at 80 K to 5.31 BM at 301 K, and was interpreted by a spin-spin interaction model based on a binuclear structure with an antiferromagnetic interaction parameter of J=−10 cm−1 (S1=S2=5⁄2), while the magnetic moment for [FeCl(salacen)] is 5.86 BM at 80 K and 5.96 BM at 302 K, indicating that the complex is a monomeric species of high-spin type. The bis(imidazole)iron(III) complexes [Fe(im)2(salacen)] BPh4·CH3OH and [Fe(im)2(hapacen)]BPh4·2CH3OH showed a striking thermochromic behavior in various organic solvents, changing from dark red to green with decrease of the temperature. The complexes are essentially of low-spin type in solids, where im and BPh4 denote imidazole and tetraphenylborate, respectively. Electronic, 1H NMR (Evans method), and ESR spectra confirmed that the thermochromism is caused by spin-equilibrium between high-spin(S=5⁄2) and low-spin(S=1⁄2) states of iron(III).
Type of Medium:
Online Resource
ISSN:
0009-2673
,
1348-0634
DOI:
10.1246/bcsj.57.3307
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
1984
detail.hit.zdb_id:
2041163-7
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