Dicyanonitrosomethanide as a Subject of Nucleophilic Addition of Methanol and as an End-O-Coordinated Ligand in the Same Copper(II) Complex. II. (Bipyridine)(dicyanonitrosomethanido)[methyl(2-cyano-2-hydroxyimino)ethanimidato]copper(II)

A new ligand formation was observed in the title complex, (bipyridine-N,N')(dicyanonitrosomethanido-O)(3-imino-3-methoxy-2-nitrosoacrylonitrilato-N²,N³) copper(II), [Cu(C₄H₄N₃O₂)(C₃N₃O)(C₁₀H₈N₂)], as a result of the nucleophilic addition reaction between a dicyanonitrosomethanide anion (ndcm), [ONC(CN)₂]^-, and a methanol molecule, CH₃OH, in the inner coordination sphere of the Cu^II atom. This new ligand, the methyl(2-cyano-2-hydroxyimino)ethanimidate anion (mcoe), [ONC(CN)C(NH)OCH₃]^-, is coordinated as a chelate, forming a five-membered metallocycle with the Cu^II atom. Thus, the distorted tetragonal-pyramidal coordination of the Cu^II atom is formed by one chelate-coordinated molecule of 2,2'-bipyridine (bipy), one chelate-coordinated mcoe ligand and one end-O-coordinated ndcm. The four N atoms of the two metallocycles form the base, and the fifth O atom of the ndcm anion forms the apex of the tetragonal pyramid, creating a {CuN₄O} chromophore. The structure of [Cu(bipy)(mcoe)(ndcm)] consists of discrete molecules. This compound is the first example in which one ndcm anion serves as a subject of nucleophilic addition reaction and another one as an end-O-coordinated ligand.

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