A Michael-type reaction between acrylato ions and ethylenediamine coordinated to Ni(II). Synthesis, crystal structure and magnetic properties of [Ni2(EDDP)2(H2O)2] · 2H2O (H2EDDP = ethylenediamine-N,N-dipropionic acid)

摘要

The reaction between NiCO3 · Ni(OH)2, acrylic acid and ethylenediamine in a 2:4:1 molar ratio affords the binuclear complex, [Ni2(EDDP)2(H2O)2] · 2H2O 1. The organic ligand, EDDP~(2-) (the dianion of the ethylene-diamine-N,N-dipropionic acid ligand), results from the addition of one amine group to the carbon-carbon double bonds of two acrylato ions. The crystal structure of 1 consists of neutral centrosymmetric entities, with the nickel ions connected by two carboxylato groups, each one acting as a monoatomic bridge. The intramolecular Ni...Ni distance is 3.212 A. The metal ions exhibit an octahedral geometry. The cryomag-netic investigation of 1 reveals an antiferromagnetic coupling of the nickel(II) ions (J = -21.8cm~(-1),h = -JS_(Ni1)S_(Ni2)).