Role of the kinetic template effect in the preparation of an original copper complex

Reaction of diethylenetriamine with phenol derivatives possessing a phenyl ester function yields a ligand corresponding to the monocondensation of diethylenetriamine with the phenol derivative. In a following step, its coordination to copper ions gives a neutral complex that is able to react with orthovanillin in order to yield an original complex made of a non symmetric ligand possessing three nitrogen, amide, imine and secondary amine, and four oxygen, amide, phenol (2) and methoxy donor atoms, thanks to the kinetic template effect. In our example, the copper center brings the three reactive functions (first primary amine and aldehyde, then amide) in close vicinity so that the formation of an imine function and the protonation of the amide function can occur. The structural determination of the resulting complex confirms an unexpected copper coordination. (C) 2018 Elsevier Ltd. All rights reserved.