NICKEL(2) COMPLEXES OF NEW MACROCYCLIC LIGANDS MESO- AND RAC2,12-DIMETHYL-3,7,11,17-TETRAAZABICYCLO[11.3.1]HEPTADECA-1(17),13,15-TRIENE

Hydrogenation under mild conditions of the macrocyclic complex 2,12-dimethyl-3,7,11,17-tetraazabicyclo [11.3.1] heptadeca-1(17),2,11,13,15-pentaenenickel(II), abbreviated Ni(CR)2+, yields two new isomeric complexes. The process hydrogenates the two azomethine linkages and produces two asymmetric carbon centers. The observed isomerism is due to the resulting meso and racemic ligand forms. Stereochemical considerations and derivatives have permitted identification of the more abundant (~10:1) red isomer as the meso structure. The meso form folds to admit the donors of bidentate ligands onto pairs of adjacent coordination sites, e.g., oxalate or ethylenediamine. A variety of derivatives Ni(CRH)X2.xH2O [X = Cl, Br, I, ClO4, BF4, NO2, NCS, N3, or 0.5C2O4] have been prepared and characterized. © 1969, American Chemical Society. All rights reserved.