Template reaction of [Ni(ben)(3)](ClO4)(2) with acetone. Crystal structureof 1,11-bis-benzyl-5,7,7-trimethyl-1,4,8,11-tetra-aza-undeca-4-ene nickel(II) perchlorate

The template synthesis of a new open-chain tetra-aza ligand derived from N- benzylethylenediamine is reported. X-ray structural analysis of the title c ompound has been determined. C-13 CP-MAS NMR for the [Ni(benacet)](CIO4)(2) complex was made and assignment of the signals was carried out by the use of the open gate decoupling technique and by comparison with the Ni(II) and Zn(II) complexes of the trans-[14]diene ligand as well as with the perchlo rate salt of the free macrocycle. Based on the type of isolated compound, a hypothesis of the possible mechanism of reaction that explains the formati on of the mesityl moiety during the template reaction is discussed. This hy pothesis could also be used to explain how in the original reaction made by Curtis, a mixture of cis- and trans-isomers are formed. (C) 2000 Elsevier Science B.V. All rights reserved.