The adsorption capability of alpha-diimines N-ethylamine-1,2-dimethyl-alpha-diimine, N-ethylhydroxy-1,2-dimethyl-a-diimine and N-ethylthiol-1,2-dimethyl-alpha-diimine over iron-clusters was studied by DFT. The results show that since these compounds possess suitable structural and electronic parameters for metal adhesion, alpha-diimines strongly adsorb over the metal clusters. Moreover, the calculated binding energy supports the existence of a bond between alpha-diimine and the iron metal, consisting of the transfer of high-charge density which in the delocalization region (N1=C2-C3=N4) is formed by p (nitrogen) and pi (C=N) to the metal (L(sigma) --> Fe). Furthermore, the binding nature of the compounds with the metal is then confirmed in molecular orbital studies by detecting the overlap of HOMO (diimines) with LUMO (iron). (C) 2009 Elsevier B. V. All rights reserved.