Mössbauer spectra of square-planar organometallic compounds of iron(II)

Abstract

Mössbauer spectra of [Fe(C 6Cl 5) 2L 2], L = PEt 3 and PEt 2Ph have been recorded at different temperatures. The low δ values show a high degree of covalency in the ironligand bonds, and the large Δ values are consistent with a planar geometry. The Mössbauer emission spectra of some [ 57Co(C 6Cl 5) 2L 2] (L = PEt 3, PEt 2Ph or PEtPh 2) show no Mössbauer effect, suggesting the formation of a new iron specimen during the 57Co(EC) 57Fe reaction, with an extremely small f-factor. [Fe(C 6Cl 5) 2L 2] compounds have been prepared either from the reaction of C 6Cl 5MgCl and [FeCl 2L 2] or by the addition of the phosphine to a solution of the ‘Fe(C 6Cl 5) 2’ complex. The stability of these complexes has been studied in different solvents and in the presence of bromine.