Complexes with New Chelate Anionic Ligands Formed by Nucleophilic Addition in Copper(II) Coordination Sphere. III. The Crystal Structures of (2,2'-Bipyridine- N,N' )(cyanato- N )[methyl(2-cyano-2-imidoxy Ethaneimidate- N,N' )]copper(II) and (2,2'-Bipyridine- N,N' )(2-cyano-2-imidoxy Ethaneimidate- N
Crystal structures of Cu(II) compounds with new chelate anionic ligands are presented. The formulae of these compounds are [Cu(bipy)(mcoe)(NCO)] ( 1 ) and [Cu(bipy)(coe)] ( 2 ), where bipy is 2,2'-bipyridine, mcoe and coe are the anionic chelate ligands methyl(2-cyano-2-imidoxy ethaneimidate), [(ON)(NC)C-C(NH)(OCH 3 )] 1- ( 3 ), and 2-cyano-2-imidoxy ethaneimidate, [(ON)(NC)C-C(NH)(O)] 2- ( 4 ), respectively, formed by nucleophilic addition of methanol and hydroxide ion to the coordinatively activated β-carbon of the nitroso-dicyanomethanide. Formation of the hydroxide ion from water in the reaction mixture can be explained by protonation of the C(CN) 3 - anion. The coordination polyhedra in 1 and 2 are quite different. The coordination polyhedron around the Cu(II) ion in 1 is a distorted trigonal bipyramid and in 2 a distorted square. The Cu(II) ion in 1 is coordinated by four N atoms from two bidentate ligands and one N atom from the NCO - group. The crystal structure consists of discrete molecules with {CuN 5 } chromophore. On the other hand, the Cu(II) ion in 2 is coordinated by four N atoms from two bidentate ligands in square coordination and the molecules are linked by weaker contacts between copper and oxygen atoms (Cu-O1 i = 2.503(3), Cu-O2 ii = 2.801(3) A; i = - x , - y , - z  + 1; ii = - x  + 1, - y , - z  + 1) to infinite chains parallel with c . Thus the coordination polyhedron is completed to an elongated tetragonal bipyramid with the {CuN 4 O*O*} chromophore. The angle O1 i -Cu-O2 ii is 167.9(1)° and the crystal structure cannot be considered as molecular but consisting of chains running in one direction. Inspection of the bond distances in mcoe and coe indicates strongly delocalized π-bonding systems. This is also supported by the fact that the anions are almost planar with bond angles close to 120°. The calculated Wiberg (bond-order) indices show that due to conjugation, the bonds within the metallocycle in mcoe and coe exhibit partially multiple character.