Fe~(II)Pd~(II) and Fe~(III) complexes of macrocyclic compartmental ligands: different cyclization in stepwise template synthesis using Fe~(II)/Pb~(II) or Fe~(III)/Pb~(II) pairs

摘要

The reaction of [bis(3-formyl-5-methylsalicylidene)ethylenediaminato] iron (II) with diethylenetriamine (dien) in the presence of Pb~(II) followed by the addition of NaNCS formed a Fe~(II)Pb~(II) complex, [FePb(L~1)(NCS)(dmf)(ClO_4)] 1, where (L~1)~(2-) is a dinucleating macrocyclic compartmental ligand derived from the [2:1:1] condensation of 2, 6-diformyl-4-methylphenol, ethylenediamine and dien, having "salen"- and "saldien"-like metal-binding sites sharing the phenolic entities. The Fe resides in the "salen" site and the Pb in the "saldien" site: the Fe...Pb intermetallic separation is 3.438 (2) A. The Fe assumes a square-pyramidal geometry with an isothiocyanate nitrogen at the apex. The Pb has a seven-coordinate geometry with a dmf oxygen and a perchlorate oxygen at the axial sites. Complex 1 reacts with molecular dioxygen to give a #mu#-oxo complex [{FePb(L~1)(NCS)(dmf)(ClO_4)}_2]. A similar reaction of chloro [bis(3-formyl-5-methylsalicylidene) ethylenediaminato] iron (III) with dien in the presence of Pb~(II) formed a mononuclear Fe~(III) complex [Fe(H_2L~2)(NCS)][ClO_4]_2 centre dot dmf 2, where H_2L~2 is a macrocycle derived from the [2:2] condensation of 2, 6-diformyl-4-methylphenol and dien. The Fe resides in one "saldien" site and assumes an octahedral geometry with an isothiocyanate nitrogen in one apical position. Another metal-binding site formed with dien shows unusual condensation; one primary amino group of the dien condenses with one formyl group to form an usual C=N linkage and the remaining primary and secondary amino groups of the dien condense with another formyl group to form a five-membered imidazoline ring.