From computational chemistry simulations, a ligand has emerged that could be selective of Pb 2+ toward Zn 2+ and Ca 2+ , an important point when designing new chelators usable in vivo as remediation agents against lead poisoning (saturnism). Some electronic properties of 1,4,7,10,13,16-hexaoxa-cyclooctadeca-2,5,8,11,14,17-hexaene (hoc-18) are examined here in details, together with those of some thio-analogs. Several interpretative ab initio methodologies that allow clarifying a number of characteristics of hoc-18 towards Zn 2+ , Ca 2+ and Pb 2+ are considered from the viewpoint of coordination chemistry.