Mono- and Binuclear Complexes of Iron(III) with 1,2-Bis(2-hydroxybenzamido)ethane

Abstract

Complexes of the type [(Fe(L))2O]ċH2O (H2L=1,2-bis(2-hydroxybenzamido)ethane), [(Fe(L))2ter]ċ5H2O H2ter=terephthalic acid), [Fe(L)bpy]BPh4 (bpy=2,2′-bipyridyl), and [Fe(L)phen]ClO4ċH2O (phen=o-phenanthroline) were prepared and studied by elemental analysis, magnetochemical measurements, and spectroscopic methods. [(Fe(L))2O]ċH2O and [(Fe(L))2ter]ċ 5H2O are probably binuclear, and the weak antiferromagnetic exchange interaction, (μeff per one atom of iron(III) was found to be 3.59 BM/77 K−4.91 BM/290 K (J=−7 cm−1, H=−2JS1S2, S1=S2=5/2) for the μ-oxo complex and 4.21 BM/82 K−5.35 BM/297 K (J=−5 cm−1) for the μ-terephthalato complex. The iron(III) complexes with bpy or phen are probably mononuclear; their anomalous μeff values (3.51 BM/80 K−3.68 BM/297 K for (Fe(L)bpy]BPh4 and 4.93 BM/259 K for [Fe(L)phen]ClO4ċH2O, respectively) agree neither with high spin (5.7–6.1 BM) nor with low spin (2.1–2.5 BM) configurations.