Oxidative Dehydrogenation of Hexaaza Macrocyclic Nickel(II) Complexes Bearing Two N-Alkyl Pendant Arms: Preparation of New Complexes Containing Imidoylamidine Linkages

摘要

Metal-promoted reactions of coordinated organic compounds, such as oxidative dehydrogenation reactions, have attracted particular attention because of their potential applications in organic chemistry, catalysis, and biochemistry. The saturated tetraaza macrocyclic nickel(II) complex [NiL~5]~(2+) is known to react with HNO3 to yield [NiL~6]~(2+) containing four isolated imino groups. The reaction of [NiL~7]~(2+) with HNO3 produces [NiL~8]~(2+) and [NiL~9](2+) containing only one or two imino groups in the six-membered chelate ring(s). On the other hand, [NiL~(10)]~(2+) reacts with H2O2 to produce the dinuclear complex [Ni_2L~(11)]~(4+), in which two unsaturated macrocyclic units are linked together by a C=C bond. Literature up to date clearly shows that the number and position of the imino groups in the product is strongly influenced by the structural characteristics of the macrocycle.