Polydentate aliphatic amines

Complexes of Some Transition Metals with Polydentate Aliphatic Amines... 

The implication of active lanthanide ion participation in labile ligand-metal interactions is ratho unexpected, considering the thermodynamic stabiUty of complexes formed between ions and polydentate aliphatic amines in acetonitrile (Forsberg, 1973). 

It was obvious to chemists in the early twenties that an extension of Werner s ideas into compounds with polydentate ligands involved the syntheses of suitably constituted, organic substances. Among these were the higher homologs of aliphatic amines related structurally to 1, 2-diaminoethane (en), dH, 2-diaminopropane (pn), and 1, 3-diaminopropane (tn). Efficient synthetic routes to these long-chain bases were at best tedious and frequently very difficult with conventional laboratory equipment. 

Many aliphatic polydentate amines form stable iron(II) octahedral complexes and in some instances these are obtained directly from Fe precursors. Thus anhydrous ethylenediamine or propylenediamine react with FeCl3 to give octahedral [Fe(en)3]Cl2 and [Fe(pen)3]Cl2 respectively. In contrast bis(2-dimethylaminoethyl)methylamine reacts with FeClj in hot butanol to yield amethyst, air sensitive crystals of high-spin = 5.2 BM) five-coordinate [Fe(dien)Cl2]. A munber... 

---